Systems and methods for analyzing remote sensing imagery

ABSTRACT

Disclosed systems and methods relate to remote sensing, deep learning, and object detection. Some embodiments relate to machine learning for object detection, which includes, for example, identifying a class of pixel in a target image and generating a label image based on a parameter set. Other embodiments relate to machine learning for geometry extraction, which includes, for example, determining heights of one or more regions in a target image and determining a geometric object property in a target image. Yet other embodiments relate to machine learning for alignment, which includes, for example, aligning images via direct or indirect estimation of transformation parameters.

RELATED APPLICATION

This application is a divisional of Ser. No. 16/833,313 filed 27 Mar.2020, which is a continuation of U.S. Non-Provisional patent applicationSer. No. 16/353,345, which was filed 14 Mar. 2019, which is a divisionalof U.S. Non-Provisional patent application Ser. No. 15/253,488, whichwas filed on 31 Aug. 2016, which further claims the benefit of thefollowing applications: U.S. Provisional Patent Application No.62/212,424, which was filed on 31 Aug. 2015 and U.S. Provisional PatentApplication No. 62/315,180, which was filed on 30 Mar. 2016; all of theforegoing patent applications are incorporated herein by reference intheir entirety for all purposes.

BACKGROUND OF THE INVENTION Technical Field

Embodiments of the present disclosure relate to the field of remotesensing, deep learning, and object detection.

Description of the Related Art

Structural and geospatial data are valuable in areas such as, forexample, real estate transaction, planning, and/or insurance.Non-limiting examples of the structural and geospatial data include thefollowing: the area of real property including land and/or buildings;the square footage of a building; the roof size and/or type; thepresence of a pool and its size and/or location; and the presence oftrees and its type, size, and/or location.

Traditionally, the structural and geospatial information can be obtainedby (1) manually checking real estate records from relevant agencies; or(2) manually surveying the underlying real properties. These traditionalmethods suffer from a number of drawbacks and deficiencies. First, therecords can be out of date, missing, or destroyed. Second, the manualchecking and surveying are labor intensive and costly. Third, surveyingarea such as the roof of a building or the crown of a tree can bedangerous.

Therefore, there is a need in the art to provide systems and methods forobtaining structural and geospatial data that overcome these drawbacksand deficiencies.

SUMMARY

In accordance with the disclosed subject matter, systems, methods, andcomputer readable media are provided for remote sensing, deep learning,and detecting object.

A method of identifying a class of a pixel in a target image accordingto one embodiment of the present disclosure can include receiving, at anobject detector, training images, wherein each training image includespixels; receiving, at the object detector, labels, wherein each labelassociates a class to each of the pixels of the training images;creating, at the object detector, a classifier configured to identifythe class of each pixel based on the training images and the labels;receiving, at the object detector, a target image; dividing, at theobject detector, the target image into a plurality of divisions, whereineach division includes a plurality of pixels; selecting, at the objectdetector, a target pixel from the plurality of pixels; and determining,at the object detector using the classifier, a target class for thetarget pixel of the target image by comparing the target pixel toneighboring pixels from the plurality of pixels.

According to some embodiments, the method can further include generatinga segmented image based on the target image and the determined targetclass for the target pixel.

According to some embodiments, the segmented image can be generatedusing one of a graph-cut, GrabCut, conditional random fields, or manualtechnique.

According to some embodiments, each of the training images and thetarget image can be one of a red-green-blue, panchromatic, infrared,ultraviolet, multi-spectral, or hyperspectral image.

According to some embodiments, the classifier can be created using aconvolutional neural network.

According to some embodiments, the neighboring pixels can be immediatelyadjacent to the target pixel.

According to some embodiments, each of the class and the target classcan be at least one of a building, roof, pool, road, trampoline,automobile, truck, boat, plane, communication tower, power transmissiontower, hedge, porch, patio, deck, or a tree trunk.

A method of generating a label image based on a parameter set accordingto one embodiment of the present disclosure can include receiving, at anobject detector, training images; receiving, at the object detector,training parameter sets, wherein each of the training parameter setscorresponds to a transformed representation of one or more labels, andwherein the one or more labels correspond to a different training image;creating, at the object detector, a classifier configured to determine aparameter set for an image based on the training images and the trainingparameter sets; receiving, at the object detector, a target image;determining, at the object detector using the classifier, a targetparameter set that corresponds to one or more target labels for thetarget image, wherein the target parameter set corresponds to a targettransformed representation of the one or more target labels; andgenerating, at the object detector, a label image by applying an inversetarget parameter set to the target image, wherein the inverse targetparameter set corresponds to an inverse transformation of atransformation represented by the target parameter set, wherein one ormore pixels of the label image are associated with a class.

According to some embodiments, each of the one or more classes can beeither two-class or multi-class.

According to some embodiments, the method can further include receivingsecond training parameter sets for the training images, wherein thesecond training parameter sets comprise at least one of time, date, sundirection, sun position, latitude, or longitude.

According to some embodiments, each of the training parameters sets andthe target parameter set can represent a transformation created usingone of discrete cosine transform, wavelets, discrete Fourier transform,principal component analysis, non-negative Matrix Factorization, orHadamard transform.

According to some embodiments, each of the training images and thetarget image can be one of a red-green-blue, panchromatic, infrared,ultraviolet, multi-spectral, or hyperspectral image.

A method of determining heights of one or more regions in a target imageaccording to one embodiment of the present disclosure can includereceiving, at an extractor, training images, wherein each of thetraining images includes one or more regions, wherein each regionincludes one or more pixels; receiving, at the extractor, labels thatindicate a height for each pixel of the one or more regions of eachtraining image; creating, at the extractor, a regression modelconfigured to determine a height of a region based on the trainingimages and the labels; receiving, at the extractor, a target imagecomprising a target region; and determining, at the extractor using theregression model, a height of the target region in the target image.

According to some embodiments, each of the training images and thetarget image can be one of a red-green-blue, panchromatic, infrared,ultraviolet, multi-spectral, or hyperspectral image.

According to some embodiments, receiving the training images can includereceiving the training images from one or more sensors at fixedpositions.

According to some embodiments, receiving the training images can furtherinclude receiving orientations of the sensors relative to one another ifthe training images are from two or more sensors.

According to some embodiments, receiving the training images can includereceiving the training images from one or more sensors and parametersrelated to at least one of one or more positions of the one or moresensors, orientation of illumination source that associates formation ofthe training images, time, date, latitude, or longitude.

According to some embodiments, the training images can be projected ontoa same geographic surface that defines the one or more regions.

According to some embodiments, the method can further include receiving,at the extractor, parameters related to positions of one or more sensorsconfigured to capture the training images.

A method of determining a geometric object property in a target imageaccording to one embodiment of the present disclosure can includereceiving, at an extractor, training images; receiving, at theextractor, a geometric object corresponding to a portion of one or moreof the training images; receiving, at the extractor, training geometricobject properties, wherein each of the training geometric objectproperties identifies a corresponding geometric object; receiving, atthe extractor, first one or more parameters related to orientation ofillumination source that associates formation of the training images forthe training images; creating, at the extractor, at least one of aclassifier or a regression model configured to determine a geometricobject property for an image based on the training images, the geometricobject, the training geometric object properties, and the first one ormore parameters; receiving, at the extractor, a target image; receiving,at the extractor, a target geometric object corresponding to a portionof the target image; receiving, at the extractor, second one or moreparameters related to orientation of illumination source that associatesformation of the target image; and determining, at the extractor usingthe at least one of a classifier or a regression model, a targetgeometric object property associated with the target geometric object.

According to some embodiments, each of the training images and thetarget image can be one of a red-green-blue, panchromatic, infrared,ultraviolet, multi-spectral, or hyperspectral image.

According to some embodiments, the training geometric object propertycan be at least one of slope, pitch, dominant pitch, material, area,height, or volume, and the target geometric object property can be atleast one of slope, pitch, dominant pitch, material, area, height, orvolume.

According to some embodiments, the geometric object can be at least oneof a point, a contour, an area, or a binary mask, and the targetgeometric object can be at least one of a point, a contour, an area, ora binary mask.

According to some embodiments, the first one or more parameters caninclude at least one of time, date, sun direction, sun position,latitude, longitude, or object material, and the second one or moreparameters can include at least one of time, date, sun direction, sunposition, latitude, longitude, or object material.

A method of aligning images according to one embodiment of the presentdisclosure can include receiving, at an aligning device, N first type ofimage sets, wherein N>1, wherein each of the N first type of image setsincludes one or more first type of images; receiving, at the aligningdevice, N second type of image sets, wherein each of the N second typeof image sets includes different one or more second type of images,wherein each of the N second type of image sets is aligned with adifferent one of the N first type of image sets; generating, at thealigning device, M transform parameters, wherein M>1; generating, at thealigning device, M transformed second type of image sets for each of theN first type of image sets so that there are N*M total transformedsecond type of image sets, wherein each of the M transformed second typeof image sets for each of the N first type of image sets is generated bytransforming a respective one of the N second type of images sets usinga different one of the M transform parameters; creating, at the aligningdevice, a regressor configured to identify parameters of atransformation that maps a second type of image set to a first type ofimage set, wherein the regressor is created based on the N first type ofimage sets, the M transform parameters, and the N*M total transformedsecond type of image sets; receiving, at the aligning device, a targetfirst type of image set and a target second type of image set;generating, at the aligning device using the regressor, a targettransform parameter based on the target first type of image set and thetarget second type of image set; and generating, at the aligning device,a transformed target second type of image set by transforming the targetsecond type of image set using the target transform parameter so thatthe transformed target second type of image set is aligned with thetarget first type of image set.

According to some embodiments, the first type of images can bered-green-blue images, and the second type of images can be parcel maps.

According to some embodiments, each image in the first type of imagesets, the second type of image sets, the target first type of image set,and the target second type of image set can be one of a red-green-blue,panchromatic, infrared, ultraviolet, multi-spectral, or hyperspectralimage.

According to some embodiments, the method can further includedetermining, at the aligning device, whether the target transformparameter results in convergence.

According to some embodiments, the method can further include thefollowing: if it is determined that the target transform parameter doesnot result in convergence, performing the following steps untilconvergence: (1) generating, at the aligning device, a new targettransform parameter; and (2) determining, at the aligning device,whether the new target transform parameter results in convergence.

According to some embodiments, one or more of the N first type of imagesets can include a plurality of co-registered first type of images.

According to some embodiments, the transform parameters and the targettransform parameter can be for at least one of translation, similarity,perspective, thin-plate-splines, piece-wise affine, B-spline, orhigh-order bivariate polynomials.

A method of aligning images according to one embodiment of the presentdisclosure can include receiving, at an aligning device, N first type ofimage sets, wherein N>1, wherein each of the N first type of image setsincludes one or more first type of images; receiving, at the aligningdevice, N second type of image sets, wherein each of the N second typeof image sets includes different one or more second type of images,wherein each of the N second type of image sets is aligned with adifferent one of the N first type of image sets; creating, at thealigning device, a regressor configured to identify a second type ofimage set given a first type of image set, wherein the regressor iscreated based on the N first type of image sets and the N second type ofimage sets; receiving, at the aligning device, a target first type ofimage set and a plurality of first key points of the target first typeof image set; receiving, at the aligning device, a target second type ofimage set; dividing, at the aligning device, the target first type ofimage set into a first plurality of divisions, wherein each of the firstplurality of divisions is centered around a different one of theplurality of first key points; generating, at the aligning device usingthe regressor, a second plurality of divisions of the target second typeof image set based on the first plurality of division of the targetfirst type of image set; identifying, at the aligning device, aplurality of second key points, wherein each second key point is from adifferent division of the second plurality of division; identifying, atthe aligning device, transform parameters that maps the plurality ofsecond key points to the plurality of the first key points; andgenerating, at the aligning device, a transformed target second type ofimage set by transforming the target second type of image set using thetransform parameters so that the transformed target second type of imageset is aligned with the target first type of image set.

According to some embodiments, each image in the first type of imagesets, the second type of image sets, the target first type of image set,and the target second type of image set can be one of a red-green-blue,panchromatic, infrared, ultraviolet, multi-spectral, or hyperspectralimage.

According to some embodiments, the transform parameters can be for atleast one of translation, similarity, perspective, thin-plate-splines,piece-wise affine, B-spline, or high-order bivariate polynomials.

According to some embodiments, one or more of the N first type of imagesets can include a plurality of co-registered first type of images.

The present disclosure also discloses systems that are operative toperform the method steps described above. Disclosed systems can includebut not limited to a processor, memory, storage medium (e.g., localstorage medium, remote storage medium), communication network, server(e.g., imagery analysis server), device (e.g., imagery acquisitiondevice, client device), module (e.g., analytical module), web service,and pipeline.

The present disclosure also discloses computer readable media thatinclude executable instructions (e.g., computer program of instructions)operable to cause a system to perform the method steps described above.

There has thus been outlined, rather broadly, the features of thedisclosed subject matter in order that the detailed description thereofthat follows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the disclosed subject matter that will bedescribed hereinafter and which will form the subject matter of theclaims appended hereto.

In this respect, before explaining at least one embodiment of thedisclosed subject matter in detail, it is to be understood that thedisclosed subject matter is not limited in its application to thedetails of construction and to the arrangements of the components setforth in the following description or illustrated in the drawings. Thedisclosed subject matter is capable of other embodiments and of beingpracticed and carried out in various ways. Also, it is to be understoodthat the phraseology and terminology employed herein are for the purposeof description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the disclosed subject matter. It isimportant, therefore, that the claims be regarded as including suchequivalent constructions insofar as they do not depart from the spiritand scope of the disclosed subject matter.

These together with the other objects of the disclosed subject matter,along with the various features of novelty which characterize thedisclosed subject matter, are pointed out with particularity in theclaims annexed to and forming a part of this disclosure. For a betterunderstanding of the disclosed subject matter, its operating advantagesand the specific objects attained by its uses, reference should be madeto the accompanying drawings and descriptive matter in which there areillustrated preferred embodiments of the disclosed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features, and advantages of the disclosed subjectmatter can be more fully appreciated with reference to the followingdetailed description of the disclosed subject matter when considered inconnection with the following drawings, in which like reference numeralsidentify like elements.

FIG. 1A illustrates an image of a residential neighborhood including apool.

FIG. 1B illustrates a heat map representing the likelihood of thepresence of a pool or some other structure.

FIG. 2 illustrates a method for producing a heat map for identifyingroofs in an image.

FIG. 3 illustrates method for automatically identifying a class of apixel according to some embodiments of the present disclosure.

FIG. 4 illustrates an example of automatically identifying a class of apixel according to some embodiments of the present disclosure.

FIG. 5A illustrates an example of detecting objects using manuallyidentifying labels.

FIG. 5B illustrates an example of detecting objects according to someembodiments of the present disclosure.

FIG. 6 illustrates an example of generating labels for a subset ofdivisions for an image according to some embodiments of the presentdisclosure

FIG. 7 illustrates an application of segmentation encoding for efficientpixel classification according to some embodiments of the presentdisclosure.

FIG. 8 illustrates examples of input and output for a classifieraccording to some embodiments of the present disclosure.

FIG. 9 illustrates an example portion of a label space in multi-labelclassification according to some embodiments of the present disclosure.

FIGS. 10A, 10B, and 10C respectively illustrate an example set of a DSMimage, a DEM image, and an AGH image according to some embodiments ofthe present disclosure.

FIGS. 11A, 11B, and 11C respectively illustrate an example set of a DSMimage, a DEM image, and an AGH image according to some embodiments ofthe present disclosure.

FIG. 12 illustrates a method of determining heights of one or moreregions in an image according to some embodiments of the presentdisclosure.

FIG. 13 illustrates example images in a feature space and a label spaceaccording to some embodiments of the present disclosure.

FIG. 14 illustrates a method for determining a geometric object propertyaccording to some embodiments of the present disclosure.

FIG. 15 illustrates a method for training a classifier model (e.g., aCNN) for learning the parameters of a transformation that maps the spaceof geospatial imagery to the space of parcel boundaries according tosome embodiments of the present disclosure.

FIG. 16 illustrates a method for identifying parameters of atransformation that maps a first type of image set to a second type ofimage set according to some embodiments of the present disclosure.

FIG. 17 illustrates a training example that uses sample input, transformparameters, and pairs of feature space and transform parametersaccording to some embodiments of the present disclosure.

FIG. 18 illustrates a method of aligning images based on identifying asecond type of image set given a first type of image set according tosome embodiments of the present disclosures.

FIGS. 19A and 19B illustrate an example of an RGB image andcorresponding images of different multi-spectral bands.

FIG. 20 illustrates examples involving the use of images representingthe expectation taken over the predicted distribution of local binarysuper pixels according to some embodiments of the present disclosures.

FIG. 21 illustrates a method for generating a label image based on aparameter set according to some embodiments of the present disclosure.

FIG. 22 illustrates an example input and output of the classifieraccording to some embodiments of the present disclosure.

FIG. 23 illustrates an example input to a pseudo multi-label classifieraccording to some embodiments of the present disclosure.

FIG. 24 illustrates an example parameter set and a label map formed fromthe parameter set according to some embodiments of the presentdisclosure.

FIG. 25 illustrates an example RGB image and an example AGHM imageaccording to some embodiments of the present disclosure.

FIG. 26 illustrates a system for analyzing remote sensing imageryaccording to some embodiments of the present disclosure.

FIG. 27 illustrates a block diagram of an imagery analysis serveraccording to some embodiments of the present disclosure.

FIG. 28 illustrates a top-level software architecture of a system foranalyzing remote sensing imagery according to some embodiments of thepresent disclosure.

FIG. 29 illustrates a process for the whole model setting, where aninput raster image is fed to both a heat map generation module and ageometry extraction module according to some embodiments of the presentdisclosure.

FIG. 30 illustrates a process for the parts-based model setting, wherean input raster image is fed to both a heat map generation module and ageometry extraction module according to some embodiments of the presentdisclosure.

FIG. 31 illustrates an example of a library of template shapes accordingto some embodiments of the present disclosure.

FIGS. 32A and 32B illustrate an application of autoencoders to multiplemachine learning tasks according to some embodiments of the presentdisclosure.

FIGS. 33A-33D illustrate example parameter values related to a sensoraccording to some embodiments of the present disclosure.

FIG. 34 illustrates an example of determining a geometric objectproperty according to some embodiments of the present disclosure.

FIG. 35 illustrates an example of using an object detector according tosome embodiments of the present disclosure.

FIG. 36 illustrates an example of ground truth data generated from anRGB input according to some embodiments of the present disclosure.

FIG. 37 illustrates a binary output generated from using a hybridsegmentation method according to some embodiments of the presentdisclosure.

FIG. 38 illustrates a binary output generated from using a pseudomulti-label classification method according to some embodiments of thepresent disclosure.

FIG. 39 illustrates a binary output generated from using a fullyconvolutional network according to some embodiments of the presentdisclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forthregarding the systems and methods of the disclosed subject matter andthe environment in which such systems and methods may operate, etc., inorder to provide a thorough understanding of the disclosed subjectmatter. It will be apparent to one skilled in the art, however, that thedisclosed subject matter may be practiced without such specific details,and that certain features, which are well known in the art, are notdescribed in detail in order to avoid complication of the disclosedsubject matter. In addition, it will be understood that the examplesprovided below are exemplary, and that it is contemplated that there areother systems and methods that are within the scope of the disclosedsubject matter.

Disclosed systems and methods relate to the field of remote sensing,deep learning, and object detection.

Remote Sensing

Remote sensing is a technology field that includes the remoteacquisition of sensory information. This can include, for example,satellite imagery, aerial imagery, radar, sonar, Light Detection andRanging (LIDAR), seismography, and/or any other suitable mode orcombination of modes of sensory information gathering that does notrequire direct physical contact.

Deep Learning

Deep learning is a type of machine learning where a multi-level neuralnetwork is developed and based on progressively higher levels ofabstraction. In a deep learning framework, features are typicallylearned from raw input data. This is in contrast to a shallow learningframework, which can be viewed as having one input-output layer wherehandcrafted features (e.g., Scale Invariant Feature Transform (SIFT))are used for a specific task.

A deep learning framework can be decomposed into generative anddiscriminative architectures. Generative architectures attempt tocharacterize high-order correlation properties of input data (e.g.,autoencoders) for pattern analysis or synthesis. These approachesestimate joint distributions of input data and associated classes (e.g.,as in Bayes nets). In discriminative architectures, networks aredesigned to provide discriminative power to classification by directlyestimating posterior distributions of class conditioned on the inputdata (e.g., as in convolutional neural networks). The architecture ofconvolutional neural networks (CNN) can be viewed as a cascade ofmodules consisting of a convolutional layer (which share many weightsspatially) and a pooling layer (which subsamples the output of theconvolutional layer).

Object Detection

Object detection is a process of detecting regions in images that havesemantic meaning (e.g., locating pools, gabled roofs, roads, trees inaerial imagery). Object detection methods can combine both a bottom-upand a top-down approach.

An example of bottom-up object detection is image segmentation. Imagesegmentation is a process where pixels in an image are labeled in such away that pixels sharing the same characteristics (e.g., color, texture,proximity) have the same label. In this way, an image is parceled intodistinct segments, typically in a bottom-up approach, where low-levellocal image properties are used to detect coherent regions. Imagesegmentation is often difficult in situations where noise, occlusions,shadows, etc. exist. Methods that can be used to overcome thesesituations include thresholding, clustering, edge detection, regiongrowing, and graph partitioning.

Top-down approaches for object detection often involve a training stageto obtain class-specific model features (e.g., parameters for aclassifier) that are used to generate a hypothesis for the existence ofobjects.

Embodiments of the present disclosure utilize a combined top-down andbottom-up approach.

Remote Sensing Imagery System

FIG. 26 illustrates a system 2600 for analyzing remote sensing imageryin accordance with embodiments of the present disclosure. The system2600 can include an imagery analysis server 2604, at least one clientdevice 2606 (e.g., client devices 2606-1, 2606-2, . . . 2606-N), animagery acquisition device 2608, a local storage medium 2610, and aremote storage medium 2612. All components in the system 2600 can becoupled directly or indirectly to a communication network 2602. Thecomponents described in the system 2600 can be further broken down intomore than one component and/or combined together in any suitablearrangement. Further, one or more components can be rearranged, changed,added, and/or removed. For example, in some embodiments, the system 2600can obtain the data from third-party vendors. In other embodiments, thesystem 2600 can directly acquire data through the imagery acquisitiondevice 2608.

Each client device 2606 can communicate with the imagery analysis server2604 to send data to, and receive data from, the imagery analysis server2604 via the communication network 2602. Each client device 2606 can bedirectly or indirectly coupled to the imagery analysis server 2604.Additionally, each client device 2606 can be connected to the imageryanalysis server 2604 via any other suitable device(s), communicationnetwork, or combination thereof. A client device 2606 can include, forexample, a desktop computer, a mobile computer, a tablet computer, acellular device, a smartphone, a television, or any computing systemthat is capable of performing computation.

The imagery analysis server 2604 can receive imagery data from theimagery acquisition device 2608. The imagery analysis server 2604 canextract, analyze, and/or label structural and/or geospatial informationof the received imagery data based on the techniques disclosed in thispresent disclosure. In some embodiments, a classifier can be trainedand/or maintained in the imagery analysis server 2604. The imageryanalysis server 2604 is shown as a single server; however, the imageryanalysis server 2604 can include more than one server. For example, insome embodiments, the imagery analysis server 2604 can include multiplemodular and scalable servers and/or other suitable computing resources.The imagery analysis server 2604 can support elastic computing, whichcan dynamically adapt computing resources based on demand. The imageryanalysis server 2604 can be deployed locally and/or remotely in athird-party cloud-based computing environment. In some embodiments,within the imagery analysis server 2604 or any other suitable componentof system 2600, a device or a tool—including a classifier, a regressor,an object detector, an extractor, or an aligning device that aredescribed in the present disclosure—can be implemented as softwareand/or hardware.

The imagery acquisition device 2608 can provide the imagery analysisserver 2604 with imagery data. In some embodiments, the imageryacquisition device 2608 can acquire satellite imagery, aerial imagery,radar, sonar, LIDAR, seismography, or any other suitable mode orcombination of modes of sensory information. In some embodiments, thesystem 2600 does not include the imagery acquisition device 2608 and canobtain imagery data from third-party vendors.

The system 2600 includes two storage media: the local storage medium2610 and the remote storage medium 2612. The local storage medium 2610can be located in the same physical location as the imagery analysisserver 2604, and the remote storage medium 2612 can be located at aremote location or any other suitable location or combination oflocations. In some embodiments, the system 2600 can include more thanone local storage medium, more than one remote storage medium, and/orany suitable combination thereof. In some embodiments, the system 2600may only include the local storage medium 2610 or only include theremote storage medium 2612.

The system 2600 can also include one or more relational databases, whichinclude scalable read replicas to support dynamic usage. The one or morerelational databases can be located in the local storage medium 2610,the remote storage medium 2612, the imagery analysis server 2604, and/orany other suitable components, combinations of components, or locationsof the system 2600.

The communication network 2602 can include the Internet, a cellularnetwork, a telephone network, a computer network, a packet switchingnetwork, a line switching network, a local area network (LAN), a widearea network (WAN), a global area network, or any number of privatenetworks currently referred to as an Intranet, and/or any other networkor combination of networks that can accommodate data communication. Suchnetworks may be implemented with any number of hardware and softwarecomponents, transmission media and/or network protocols. In someembodiments, the communication network 2602 can be an encrypted network.While the system 2600 shows the communication network 2602 as a singlenetwork, the communication network 2602 can also include multipleinterconnected networks described above.

FIG. 27 illustrates a block diagram of the imagery analysis server 2604in accordance with some embodiments of the present disclosure. Theimagery analysis server 2604 includes a processor 2702, a memory 2704,and an analytical module 2706. The imagery analysis server 2604 mayinclude additional modules, fewer modules, or any other suitablecombination of modules that perform any suitable operation orcombination of operations.

The processor 2702 is configured to implement the functionalitydescribed herein using computer executable instructions stored intemporary and/or permanent non-transitory memory. The processor can be ageneral purpose processor and/or can also be implemented using anapplication specific integrated circuit (ASIC), programmable logic array(PLA), field programmable gate array (FPGA), and/or any other integratedcircuit.

The processor 2702 can execute an operating system that can be anysuitable operating system (OS), including a typical operating systemsuch as Windows, Windows XP, Windows 7, Windows 8, Windows Mobile,Windows Phone, Windows RT, Mac OS X, Linux, VXWorks, Android, BlackberryOS, iOS, Symbian, or other OS.

The analytical module 2706 can be configured to cause the processor 2702or the imagery analysis server 2604 to extract, analyze, and/or labelstructural and/or geospatial information of any imagery data based onthe techniques disclosed in the present disclosure. In some embodiments,the analytical module can implement and/or execute to detect objects,extract objects, align images, and/or any other suitable task orcombination of tasks described in the present disclosure. In someembodiments, within the analytical module 2706 or any other suitablecomponent of the imagery analysis server 2604, a device or atool—including a classifier, a regressor, an object detector, anextractor, or an aligning device that are described in the presentdisclosure—can be implemented as software and/or hardware.

In some embodiments, the analytical module 2706 can be implemented insoftware using the memory 2704. The memory 2704 can be a non-transitorycomputer readable medium, flash memory, a magnetic disk drive, anoptical drive, a programmable read-only memory (PROM), a read-onlymemory (ROM), or any other memory or combination of memories.

FIG. 27 shows the imagery analysis server 2604 having the analyticalmodule 2706 that causes the processor 2702 or the imagery analysisserver 2604 to perform the operations in accordance with certainembodiments of the disclosed subject matter. The processor 2702 and/orthe imagery analysis server 2604 may include additional modules, lessmodules, or any other suitable combination of modules that perform anysuitable operation or combination of operations.

FIG. 28 illustrates a top-level software architecture of a system 2800for analyzing remote sensing imagery in accordance with some embodimentsof the present disclosure. System 2800 can include one or more of thefollowing four components: web services 2802, a Mechanical Turk (M-Turk)pipeline 2804, a training pipeline 2806, or a prediction pipeline 2808.

Web services 2802 can include one or more of the following components:front end 2810, flow control back end 2812, attribute uService 2814,attribute DB 2816, parcel service 2818, tile map service 2820, parcel DB2822, or image DB 2824. Front end 2810 can provide services to a user.For example, the user can use a browser on a workstation to connect to,and communicate with front end 2810 to execute certain web servicesfunctions, such as detecting and extracting objects from remote images.Flow control back end 2812 can communicate with front end 2810. Frontcontrol back end 2812 can implement a control flow logic and support apublic Representational State Transfer (RESTful) API to clientapplications and web-based front-end user interface. RESTful APIs cansupport lightweight, maintainable, and scalable architectures. In someembodiments, flow control back end 2812 can receive and control multiplerequests from front end 2810. Flow control back end 2812 can update thestatus of requests to front end 2810. In some embodiments, flow controlback end 2812 can receive data, such as parcel images, from parcelservice 2818, which can retrieve these parcel images from parcel DB2822. Flow control back end 2812 can also receive data, such as images,from tile map service 2820, which can retrieve these images from imageDB 2824. Flow control back end 2812 can communicate with attributeuService 2814, which can also receive images from tile map service 2820.In some embodiments, attribute uService 2814 can provide informationabout detected objects within a context. For example, Attribute uService2814 can provide information about detected roofs within RGB imageryprovided by tile map service 2820. In some embodiments, the informationcan be related to attributes that can include, for example, whether thedetected roof has solar panels, the roof footprint area, etc. In someembodiments, there can be multiple Attribute uServices, each of whichcan handle a different attribute type. Attribute uService 2814 can alsoreceive attributes from attribute DB 2816. In some embodiments, theseattributes can be related to objects in an image. For example, a slopeof a roof can be an attribute of the roof. In some embodiments, webservices 2802, using attribute uService 2814, can provide information onan attribute of an object in an image based on the image and a relatedparcel image.

M-Turk pipeline 2804 can support ground truth acquisition by, forexample, correctly labeling structures. M-Turk pipeline 2804 can includeone or more of the following components: M-Turk labeling 2826, groundtruth Candidate DB 2830, M-Turk validation 2832, or ground truth DB2828. M-Turk labeling 2826 can label images from tile map service 2820and store the labeled images in ground truth candidate DB 2830. M-Turkvalidation 2832 can determine whether the ground truth candidate(s) inground truth candidate DB 2830 is valid. In some embodiments, a groundtruth candidate can be valid if its accuracy level can be determined toexceed a threshold value. If the ground truth candidate(s) is valid, itcan be stored in ground truth DB 2828.

Training pipeline 2806 can include one or more of the followingcomponents: training 2834 and classifier 2836. Training 2834 can receivetraining images from tile map service 2820 for training. Training 2834can also receive ground truth data from ground truth DB 2828. Based onthe received training images and the received ground truth data,training 2834 can train a classifier 2836. Non-limiting examples ofspecific instances of training 2834 and classifier 2836 are described indetail below.

Prediction pipeline 2808 can include a prediction 2838 component.Prediction 2838 can use classifier 2836 to predict or classifyattributes in an image from tile map service 2820. In some embodiments,the output of classifier 2836 can provide data to prediction 2838. Insome embodiments, prediction 2838 can be used to test classifier 2836 todetermine whether classifier has been properly tested. In otherembodiments, prediction 2838 can be used during the production stage.Prediction 2838 can provide data, including results, from its operationto attribute DB 2816 for storage. In some embodiments, prediction 2838can optionally provide its data from operation to ground truth candidateDB 2830 for storage. M-Turk validation 2832 can determine whether thedata provided from prediction 2838 is valid.

In some embodiments, system 2800 can include both on-line componentsand/or off-line components. The on-line components can run in real-timeand can include one or more of the following components: (1) front-end2810 (e.g., web-based user interface); (2) flow control back end 2812;(3) tile map service 2820; (4) parcel service 2818; and (5) attributeuService 2814. In some embodiments, parcel service 2818 and/or attributeuService 2814 can be internal modules that can communicate viaJavaScript Object Notation Remote Procedure Call (JSON-RPC) protocol. Insome embodiments, internal modules are not exposed to top layerapplications. For example, when parcel service 2818 and attributeuService 2814 are internal modules, parcel service 2818 and attributeuService 2814 can logically reside behind flow control back end 2812such that they are not directly visible to front end 2810.

The off-line components can run as separate executables and populate thesystems databases, and can include one or more of the followingcomponents: (1) M-Turk Pipeline 2804; and (2) machine learning/computervision (e.g., training pipeline 2806 and prediction pipeline 2808). Insome embodiments, training pipeline 2806 and prediction pipeline 2808are implemented in modules that have their own processing pipelines. Insome embodiments, the machine learning/computer vision components canalso run on-line. In some embodiments, the on-line components can beimplemented as off-line components, the off-line components can beimplemented as on-line components, and/or any other suitable combinationthereof.

System 2800 may include additional components, less components, or anyother suitable combination of components that perform any suitableoperation or combination of operations. In some embodiments, thesecomponents can reside in a single machine, such as a server. In otherembodiments, these components can be distributed across multiplemachines.

The hardware, system, and architecture described in connection withFIGS. 26-28 can be deployed, entirely or partially, in a cloud-basedenvironment. Further, the present disclosure is not limited to theexemplary hardware and/or software arrangements described in connectionwith FIGS. 26-28 ; other suitable hardware and/or softwareimplementations are also within the spirit of the present disclosure.

Machine Learning for Object Detection

In computer vision, an image can be divided into segments, each of whichcan represent one or more objects. Each segment can include one or morepixels. Each object type can be associated with a class. A label can beused to associate a class to each pixel. If there are two or more objecttypes from which the class can be associated, the class is consideredmulti-class. For example, a red-green-blue (RGB) image taken above theground can include objects, such as, for example, roads, roofs, gardens,and pools. The RGB image can be segmented such that each pixel of theimage can correspond to, or labeled as one of the identified objects. Apixel that is part of a road can be labeled as the road class, whileanother pixel that is part of a roof can be labeled as the roof class.

In some cases, only a specific type of an object may be of interest andthus, needs to be identified. For example, one may be interested inidentifying only roofs in an image. In such cases, each pixel of animage can be labeled in a binary way (e.g., represented as a binary “1”or “0”). For example, each pixel can be labeled as either part of a roof(e.g., represented as binary “1”) or not part of a roof (e.g.,represented as binary “0”). In these cases, the class is consideredtwo-class—that is, each class corresponds to either being that object ornot being that object.

In some cases, a pixel can be labeled to indicate a probability of beingpart of a specific object. In some embodiments, the probability can be areal-valued scalar on the interval [0,1]. In some embodiments, theprobability can be expressed as a percentage. For example, each pixel ofan image can be labeled with the probability of being part of a roof,such as 0%, 20%, 50%, 93%, or 100% of being part of a roof, or any othersuitable percentage.

Model Building

In some embodiments, spatial resolution is measured by a sensor'scapability to resolve the smallest objects with distinct boundaries. Inremote sensing images, the pixel-center to pixel-center distance istypically called ground sample distance (GSD). For example, a GSD can be10 cm. In this example, sub-pixel accuracy can imply error of less than10 cm; pixel accuracy can imply error of about 10 cm; and super-pixelaccuracy can imply error of more than 10 cm. According to someembodiments, building models can be fitted with remote sensing imageryin a sub-pixel, pixel, and/or super-pixel accurate manner. These modelscan be either a whole model or a parts-based model. In both instances,2D and 3D models can be considered. In the 2D model, the height variablecan be held fixed. Per the parts-based model, an object's measures canbe taken to be more granular. For example, using the parts-based model,roof summary measures (e.g., dominant pitch, dominant gableconfiguration, etc.) can be taken to be more granular (e.g., roof iscomposed of, by area, 25% gable and 75% hip components). In the 2D modelsetting, the original 3D problem (e.g., measuring a dominant pitch isoriginally a 3D problem) can become ill-posed. To address this issue,one or more variables can be fixed. For example, the roof height can befixed, for example, with a small set of common heights.

FIG. 29 illustrates a process for the whole model setting. At step 2901,an input raster image can be used for heat map generation. At step 2904,the input raster image can be used for geometry extraction, which canassume several embodiments including, but not limited to, edge detectionand corner detection. At step 2902, the resulting heat map from step2901 can be used to produce semantically relevant objects by a processthat can assume several embodiments including, but not limited to,thresholding, clustering, active contour segmentation, and/or any of theobject detection methods discussed in this disclosure (e.g., steps oroperations described in connection with methods 300 and 2100). In someembodiments, candidate regions can be generated to identify semanticallyrelevant objects. At step 2903, whole models can be fitted to theregions. In some embodiments, polygons are fitted. At step 2905, thesemodels can be further refined using the extracted geometry from 2904 byusing, for example, the estimation of a joint probability of heat mapand edges.

FIG. 30 illustrates a process for the parts-based model setting. At step3001, an input raster image can be used for heat map generation. At step3004, the input raster image can be used for geometry extraction, whichcan assume several embodiments including, but not limited to, edgedetection and corner detection. At step 3002, the resulting heat mapfrom step 3001 can be used to produce semantically relevant objects by aprocess that can assume several embodiments including, but not limitedto, thresholding, clustering, and/or active contour segmentation. Insome embodiments, candidate regions can be generated to identifysemantically relevant objects. At step 3003, parts-based models can befitted to the regions. In some embodiments, polygons are fitted. At step3005, these models can be further refined using the extracted geometryfrom 3004 by using, for example, the estimation of a joint probabilityof heat map and edges. The distinction between this approach and thewhole model approach as shown in FIG. 29 is that extraction geometry3004 is also used to inform model selection 3003. As an example, in theparts-based model, individual facets of a roof can be modeled.

Hybrid Heat Maps

A heat map can be used to graphically represent an image to show themapping between the pixels of the image and the class conditionalprobability that corresponds to each of these pixels. In someembodiments, a segmentation can be derived from the class conditionalprobability. To distinguish one class from another, different colorschemes can be used. Non-limiting examples of color schemes includemulti-color, grayscale, and black and white.

In a multi-class label, each color can correspond to an object. Forexample, white can be used to identify a house, blue can be used toidentify a pool, and green can be used to identify a lawn in an image.In some embodiments, any other suitable color or combination of colorscan be used to identify an object. Examples of using a heat map forobject detection include semantic segmentation of large images intodifferent types of objects, such as pools, buildings, trees, andproperty parcels.

In a two-class label, each color can correspond to whether a specificpixel corresponds to the specified object. Any suitable color scheme canbe used. For example, in identifying a roof in an image, if a black andwhite scheme is used, white can be used to identify a roof, and blackcan be used to identify any other object that is not a roof, or viceversa. As another example, if a grayscale scheme is used, white can beused to identify what is certain or almost certain to be a roof (e.g.,based on a predetermined probability or percentage), and black can beused to identify what is certain or almost certain to not be a roof(e.g., based on a predetermined probability or percentage), or viceversa. In addition, shades of gray color can be used to representdifferent probabilities of an object being a roof. For example, thelighter the gray, the more likely the corresponding pixel is a roof, andthe darker the gray, the more likely the corresponding pixel is not aroof, or vice versa.

The notion of a heat map H, associated with a raster image I, can be ascalar field, where for each pixel location x, a class probability,conditioned on spatially local features over a neighborhood N(x), isdefined as H(x)=p(c(x)|I(N(x)). For example, the class c may be thestructural category or class “pool,” and the local features may be theraw image signal values (e.g., a red-green-blue (RGB) triple) in aspatial neighborhood of a given pixel location. In this setting, theheat map can represent the probability that a given pixel is part of apool. Raw image signal values may be multispectral (multiple discretenarrow bands) and hyperspectral (continuous block of narrow bands).

FIG. 1A illustrates an image of a residential neighborhood 100 aincluding a pool 102 a. FIG. 1B illustrates a corresponding heat map 100b representing the likelihood of the presence of a pool or some otherstructure. The pool 102 a in the residential neighborhood 100 a is nowrepresented as a light region 102 b in the heat map 100 b. Bar 104 ashows grayscale colors that correspond to the likelihood of presence ofa pool or some other structure. For example, a value of “1” indicatesthat it is certain that the identified object is a pool, while a valueof “0” indicates that it is certain that the identified object is not apool but another structure. In heat map 100 b, the light regions,corresponding to a value near “1,” indicates a high likelihood of thepresence of a pool (and a low likelihood of the presence of some otherstructure). And the dark regions, corresponding to a value near “0,”indicate a low likelihood of the presence of a pool (and a highlikelihood of the presence of some other structure).

Traditionally, an image could be segmented using manual hints, wheresome of the pixels of the image were manually labeled. A computer visionmethod could use these manual hints to assign labels to the remainingpixels by local similarity (e.g., color) or distance to the labeledpixels. This could be done using the so-called graph-cut approach. Usingthis approach, the computer vision method could then produce a heat mapthat segments the image.

FIG. 2 illustrates a prior art method for producing a heat map foridentifying roofs in an image. Computer vision method 206 takes in image202 and manual hints 204. Manual hints 204 are provided by a human whodraws lines that correspond to what the person sees as roofs andoptionally, what the person sees as not roofs (some other structure).Computer vision method 206 takes in these inputs, assigns a label toeach pixel of the image, and produces heat map 208. In heat map 208, thewhite areas represent the roofs in the image while the black areasrepresent non-roof areas. This conventional method has a number ofproblems. First, this method is not efficient and not scalable. Thisrequires a human to provide manual hints for each image, which is a timeconsuming process. Second, this method may not be accurate. Because thisdepends on a human to provide accurate hints, it is vulnerable to humanerrors. In addition, because the hints cover only a small portion of theimage, a lot of estimation by the computer needs to be done, whichincreases the risk of producing an inaccurate heat map.

The problems identified in the prior art can be solved by using anobject detector in accordance with some embodiments of the presentdisclosure. For example, a top-down object detection approach can beused, where heat maps are generated from trained classifiers. In oneinstance, a heat map(s) can be generated through the use of trainedconvolutional neural networks (CNNs), where either a sparse or a denseapplication of the heat map(s) can be applied to an input image.

Heat maps can be used to generate a semantic pixel labeling of the imagespace in a number of ways including via the simple threshold of a singleheat map or by maximum likelihood selection across multiple heat maps.In some embodiments, the maximum likelihood selection can be taken atthe pixel-level. As shown in heat map 100 b (FIG. 1B), heat maps may notbe fully consistent with object edges so a refinement step is oftenrequired to produce a final segmentation. In another instance, computervision methods are used to produce the pixel labeling by using the CNNgenerated heat maps as hints or weights. Examples of these computervision methods include GrabCut and conditional random fields (CRFs). InGrabCut image segmentation, an iterative optimization process can beapplied to estimating foreground and background. This approachalternates between enforcing intra-region pixel label homogeneity andapplying graph-cut optimization (max-flow min-cut) to infer pixel labelswith color distribution of foreground objects and background modeledusing a Gaussian mixture model. In the case of CRFs, a framework forconstructing probabilistic models for image segmentation can be used,where the weights of different features at different states can bebalanced against one another through a single joint exponential modelfor the joint probability.

FIG. 3 illustrates a method 300 for automatically identifying a class ofa pixel according to some embodiments of the present disclosure. In someembodiments, method 300 can be modified by, for example, having stepscombined, divided, rearranged, changed, added, and/or removed. In someembodiments, method 300 can be performed at an object detector. In someembodiments, the object detector can be located in the imagery analysisserver 2604 or any other suitable location of the system 2600.

At step 302, training images can be received. The training images caninclude one or more pixels. In some embodiments, each of the trainingimages includes more than one pixel. In some embodiments, each of thetraining images is one of red-green-blue (RGB), panchromatic, infrared(IF), ultraviolet (UV), multi-spectral, hyperspectral, and/or any othersuitable image. In some embodiments, these training images can be thesame image type. For example, these training images are all of one ofthe following image types: RGB, IR, and UV. In other embodiments, thesetraining images can be a different suitable image type or combination ofimage types. For example, of the training images, 30% can be RGB, 25%can be IR, and 45% can be UV.

At step 304, labels for the training images can be received. In someembodiments, a label can associate a class to a pixel of one of thetraining images. For example, a training image can include a roof and apool. A label can associate one of the pixels making up the roof to theroof class, while another label can be used to associate one of thepixels making up the pool to the pool class. As another example, a labelcan associate a pixel to one of the two classes—foreground andbackground. The foreground class can refer to a pixel that is part of aspecified object (e.g., object of interest), while the background classcan refer to a pixel that is not part of the specified object. A labelcan also associate a pixel to one of many classes, each of which relatesto the same object. For example, a pixel can be one of “definitelyforeground,” “likely foreground,” “definitely background” (e.g., notforeground), and “likely background” (e.g., not likely foreground). Insome embodiments, any other suitable label or combination of labels canbe used. In some embodiments, the class can be one of a building, roof,a pool, a road, a trampoline, an automobile, a truck, a boat, a plane, acommunication tower, a power transmission tower, a hedge, a porch, apatio, a deck, a tree trunk, and/or any other suitable object orcombination of objects. In some embodiments, a label can associate aclass to each of the pixels of the training images.

In some embodiments, a label can associate a class to multiple pixels ofone of the training images. For example, a label can associate all thepixels making up the roof to the roof class. In some embodiments, allthe pixels of all the training images can be associated to a class bythe received labels.

At step 306, a classifier can be created based on the received trainingimages and the received labels. The classifier can be configured toidentify the class of each pixel of an image. In some embodiments, theclassifier can be created using a machine learning system, whichincludes one or more classifiers such as an artificial neural network(ANN) including but not limited to a convolutional neural network (CNN),as would be appreciated by one of ordinary skill in the art.

At step 308, a target image can be received. In some embodiments, thetarget image is one of RGB, panchromatic, IR, UV, multi-spectral,hyperspectral, and/or any other suitable image. In some embodiments, thetarget image can be the same image type as the image type of thetraining images. For example, the image type of the target image and thetraining images can all be RGB.

At step 310, the target image can be divided into divisions. Eachdivision can include one or more pixels. For example, a division canconsist of one pixel. In another example, a division can consist of 1500pixels or any other suitable number of pixels. In some embodiments, thetarget image is divided equally, such that the area size is the same forall the divisions. For example, a 256 pixel-by-256 pixel image,consisting of 65,536 pixels, can be divided into 4,096 divisions, whereeach division consists of 16 pixels. In some embodiments, the shape ofeach division can be the same. For example, each of the 4,096 divisionscan be 4 pixel-by-4 pixel. In other embodiments, the shapes of differentdivisions can be different. For example, some of the 4,096 divisions canbe 4 pixel-by-4 pixel, while some other divisions can be 8 pixel-by-2pixel, or any other suitable size. In some embodiments, the target imageis not divided equally, such that area sizes can be different betweendifferent divisions. For example, one division can consist of 1 pixel,another division can consist of 16 pixels, and another division canconsist of 2500 pixels. In some embodiments, the division mechanism canbe configured either automatically or manually. In some embodiments, thetarget image can be divided into divisions such that one or moredivisions overlap. In other embodiments, the target image can be dividedinto divisions such that none of the divisions overlaps.

At step 312, a target pixel can be selected. In some embodiments, thetarget pixel can be from one of the divisions of the target image. Insome embodiments, the center or near-center pixel from each of thedivisions is selected as a target pixel. For example, in a 3 pixel-by-3pixel division, the center pixel that is selected as the target pixel isthe fifth pixel—counting from left to right, top to bottom (the 2^(nd)pixel from the left and 2^(nd) pixel from the top). In otherembodiments, the target pixel is selected from only some of thedivisions. For example, if a target image is divided into 1,000divisions, a target pixel from each of 300 of these 1,000 divisions canbe selected. In some embodiments, more than one target pixel can beselected from a division.

At step 314, a target class for a target pixel or pixels of the targetimage can be determined using a classifier. In some embodiments, thisclassifier is the classifier created at step 306. In some embodiments, aCNN can be used as the classifier. In some embodiments, the target classcan be determined by comparing the target pixel(s) to neighboring pixelsof the target image. For example, the color of a target pixel can becompared to the color of a neighboring pixel. If the two colors are thesame or similar, the class of the target pixel can be determined to bethe same as the class of the neighboring pixel. In some embodiments,other suitable attributes can be compared among pixels. In someembodiments, one or more of the neighboring pixels can be immediatelyadjacent to the target pixel. In some embodiments, the target class canbe one of a building, roof, a pool, a road, a trampoline, an automobile,a truck, a boat, a plane, a communication tower, a power transmissiontower, a hedge, a porch, a patio, a deck, a tree trunk, and/or any othersuitable object or combination of objects.

At step 316, a segmented image can be generated based on the targetimage and the target class determined for one or more target pixels. Insome embodiments, the segmented image can be a heat map. Varioustechniques can be used to generate the segmented image. Non-limitingexamples of techniques include graph-cut, GrabCut, CRFs, and manual. Agraph cut can be used to achieve inference (e.g., label assignment).GrabCut is a graph-based method that can be used to estimate the colordistribution of foreground and background objects using a Gaussian MixedModel (GMM). A GMM can be used to form a CRF over pixel labels, wherethe CRF is associated with discriminative models. The CRF can use anenergy function that includes a pairwise term that favors connectedregions having the same label.

In GrabCut, some or all pixels can be assigned to the foreground andbackground with weights that can indicate how likely the pixel(s) belongto the assigned class. This construct can be represented with a graph. Agraph can include nodes and edges, where the edges can describe arelationship between exactly two nodes. Additionally, an edge can havereal-valued weights assigned to it to capture a relationship between thetwo nodes. For example, a graph can capture the flight connectionsbetween airports, where each flight can be represented as an edge fromone node (airport) to another node, and the edge's weight can be thedistance, price etc. Within the context of GrabCut, the set of nodes caninclude a node for each pixel and two label nodes (often referred to asthe “source” and “sink,” each corresponding to one of background andforeground). In this setting, edges can be formed between thepixel-nodes and the label-nodes. Additionally, edges can be formedbetween pixel-nodes and their neighboring pixel-nodes, where the weightsindicate pixel similarity (e.g., closeness in color). Graph-cut can beused in GrabCut. Graph-cut can attempt to separate the sink from thesource, so that there is no path from sink to source. Graph-cut cansearch for the min-cut, which can involve looking for the set of edgesto be cut (in order to separate sink from source) with the smallest sumof their weights. A dual problem is max-flow, wherein the edge weightsare interpreted as capacities of “pipes,” and maximizing the “flow” fromsource to sink is desired. If the flow is maximized, the saturated pipesare cut.

FIG. 4 illustrates an example of using method 300 (FIG. 3 ) according tosome embodiments of the present disclosure. In some embodiments, objectdetector 404 can be used to produce binary-class heat map 410 to showroof objects. Object detector 404 can implement and execute a classifierthat can take image 402 as input. After object detector 404 divides 402into multiple divisions, object detector 404 can select a center pixelfrom each of these divisions. Object detector 404 can then determine aclass for each of these center pixels and generate label map 406 basedon the determined class. Label map 406 can include automaticallygenerated labels. In some embodiments, each white dot, such as 420, canrepresent the roof class, each black dot, such as 422, can represent thenon-roof class, and each gray dot or gray area, such as 424, canrespectively represent an unclassified dot or area. In some embodiments,the number or percentage of pixels that are given labels can becustomized manually or automatically.

Computer vision method 408 can take image 402 and label map 406 asinput. In some embodiments, computer vision method 408 can be asegmentation mechanism that takes hints or labels. Example segmentationmechanisms include a graph-cut, GrabCut, and conditional random fields.Computer vision method 408 can generate heat map 410 based on image 402and label map 406. Heat map 410 can show all the roof objects in image402 by indicating the roof objects as white areas and the non-roofobjects as black areas.

FIGS. 5A and 5B illustrate the comparison of object detection betweenusing method 500A, which is the prior art method of manually identifyinglabels, and using method 500B, which is in accordance with someembodiments of the present disclosure. Prior art method 500A takes inimage 502A as an input. 504A shows hints, which have been manuallyentered by a human. In FIG. 5A, two types of hints can be provided:foreground and background. Foreground hints 506A and 512A are used toindicate an object type of interest, while background hints 508A areused to indicate any other areas that are not part of the object type ofinterest. The segmentation method, such as GrabCut, takes image 502A andthe hints in 504A to generate a final binary foreground mask 510A.Binary foreground mask 510A shows foreground 514A and 518A in white, andbackground 516A in black.

Method 500B shows a method according to some embodiments of the presentdisclosure. Method 500B can take the same image (image 502A) as priorart method 500A. However, method 500B automatically generates labels byclassifying divisions of image 502A by using a classifier. In method500B, foreground labels 506B and 512B indicate an object type ofinterest, while background labels 508B indicate any other areas that arenot the object type of interest. The segmentation method, such asGrabCut, takes in image 502A and labels 504B to generate a final binaryforeground mask 510B. Binary foreground mask 510B shows foreground 514Band 518B in white, and background 516B in black. More pixels can beclassified in method 500B than in prior art method 500A because with theprior art method, it is impractical for a human to provide hints for alarge number of pixels. Thus, method 500B can result in a more accuratebinary foreground mask 510B than binary foreground mask 510A produced byprior art method 500A. Moreover, unlike prior art method 500A, method500B can be scalable to process a large number of pixels.

FIG. 6 illustrates an example of generating labels for a subset ofdivisions for an image according to some embodiments of the presentdisclosure. In some embodiments, a subset of total divisions, such asdivision 602 and division 604, can be selected. These selected divisionscan be used as inputs to classifier 606, which can generate labels forthese divisions. The generated labels for these divisions are shown at608 and 610, respectively. By generating labels for only a subset ofdivisions, processing time and storage can be saved. These subsets canbe chosen such that they cover objects or areas of interest, such aslocal windows, part roof, sub areas, or any other suitable object orareas of interest. In some embodiments, only the center pixel of adivision can be analyzed. In this case, the division size (e.g., thenumber of pixels per division) can be selected to provide sufficientcontext for the classifier to identify the center pixel's class.

Segmentation Encoding for Efficient Classification

Dimensionality reduction (compression) techniques for representing imagesegmentation can be used for efficient pixel foreground classification.A non-limiting example of this process includes, given an RGB image,finding a set of discrete cosine transform (DCT) coefficients that bestdescribes an implicit binary foreground segmentation. Applying theinverse DCT transformation to the coefficients produces theclassification (e.g., at each pixel, the likelihood of being aforeground object).

In some embodiments, a classifier can be trained, where inputs aregeospatial imagery (e.g., RGB and infrared images) and outputs (labelspace) are the parameters that characterize a compressed segmentation(e.g., coefficients of an orthogonal transformation).

FIG. 7 illustrates an application 700 of segmentation encoding forefficient pixel classification in accordance with some embodiments ofthe present disclosure. In some embodiments, the application 700 caninclude the following two stages: a training stage 710 and a testingstage 712. The training stage 710 can be used to train a classifier toproduce a set of parameters that can be inversely transformed to producethe resulting classification for an image. The testing stage 712 can beused to test the trained classifier from the training stage 710.

The training stage 710 can include a segmentation step 702 and a forwardtransformation step 704. At step 702, for a set of input imagery, abinary segmentation can be applied to produce corresponding foregroundmasks. Examples of segmentation include those based on techniques suchas GrabCut and manual. At step 704, a forward transformation can beapplied to the binary segmentations. In some embodiments, the mostsignificant parameters of these segmentations can characterize thecompressed version of the same. Examples of such compressiontransformation include DCT, wavelets, discrete Fourier transform,principal component analysis (PCA), non-negative Matrix Factorization(NMF), Hadamard transform, and/or any other suitable transformation. Theinput imagery associated with the binary segmentations and theirassociated compression parameters can be used to train a classifier.Examples of the classifier model include ANNs including CNNs.

After the classifier has been trained, the classifier can be tested atthe testing stage 712, which can include an “apply classifier” step 706and an inverse transformation step 708. At step 706, a test image can besupplied to the trained classifier that can produce a set of parameters(e.g., coefficients of one of the aforementioned orthogonal transform).At step 708, the inverse transformation can be applied to theseparameters to produce the resulting classification (e.g., likelihood offoreground).

FIG. 8 illustrates examples of three RGB input images (802, 804, 806)and three corresponding output images (808, 810, 812) for the trainedclassifier. These RGB input images can be used for a classifier during atesting or production stage. For example, RGB input images 802, 804, and806 can be the test images in the “apply classifier” step 706 (FIG. 7 ).The classifier can produce three sets of parameters based on these threeimages. At step 708 (FIG. 7 ), the classifier can apply the inversetransformation to these parameter sets such that the three correspondingoutput images 808, 810, and 812 are produced.

Pseudo Multi-Label Classification

In some embodiments, multi-label classification describes situationswhere multiple target labels are assigned to each input instance. Thisgeneralizes the concept of multi-class classification where eachinstance is restricted to have one class label. A common multi-labelclassification is semantic scene understanding (e.g., “this image patchcontains a roof and pool”) or segmentation (e.g., one label per pixel).

In classification, a distribution over object classes can be receivedwhen, for example, using an ANN. Thus, for a given input, a classifierthat can distinguish between a set of classes can produce a normalizedarray of real-valued numbers that reflect the likelihoods of the classesfor the given input. In some embodiments, this normalized array caninclude two real-valued numbers, where one number represents thelikelihood of a pixel being a specific object (e.g., a roof) and theother number represents the likelihood of the pixel not being thespecific object (e.g., not a roof). When a single class is desired, theclass associated with the largest real-valued number can be selected.For example, if, for a pixel, the likelihood of roof object is 0.9 andthe likelihood of not roof object is 0.1, the pixel can be classified asbelonging to a roof object.

A classifier can also be configured to produce a non-normalized array ofreal-valued scalars. In this setting, the output is not considered to bea distribution over classes and, thus, the classifier can be used tosolve a regression problem. In the context of training under pseudomulti-label classification, the set of labels are not object categories,such as “roof” and “trampoline,” but rather a set of normalized ornon-normalized array of floating point values that can be used toreconstruct the final segmentation output. In the case of regression,the non-normalized output parameters can be produced by any kind ofinvertible transformation that produces a more compact and generalizeddescription of shape. PCA and DCT are two non-limiting examples that cancompress and generalize shape (e.g., by considering most likely shapesor lower frequencies). In the case of classification, the classifier canindicate how similar the segmented version of an input image is to a setof classes (e.g., corresponding to discrete patterns). In this case, theclassifier output can be interpreted as being the likelihood that thesegmentation output looks like the pattern the class is associated with.These patterns can be shapes as “corners” and “rectangles” that arepresent in various locations within the image. The final output is thengenerated as the weighted average (or best match, etc.) of thesepatterns by using their likelihood as the weights. FIG. 9 illustratesexamples of patterns used (described below).

Instead of using multiple labels to train (which is more difficult totrain, design networks, and is slower), a single label can be used todescribe the class of a shape of an object (or pattern) to be segmentedwithin a small image chip region. In this setting, the output of theclassifier can be a probability distribution over the space of classes(patterns). A chip region can be a portion of the image. In someembodiments, a chip region can represent an area of interest. In someembodiments, an image can be processed only at chip regions such thatthe whole image does not need to be processed. In some embodiments, aheat map (e.g., where each pixel is labeled with the likelihood of beinga specific object such as a roof) can be segmented to produce a binaryimage of two classes (e.g., roof and not roof).

FIG. 9 illustrates an example portion 900 of a label space inmulti-label classification in accordance with some embodiments of thepresent disclosure. The example portion 900 can include learned patterns902, 904, 906, 908, 910, 912, 914, 916, 918, 920, 922, and 924. Thisexample illustrates the cluster centers of a k-mean process against thediscrete binary super-pixel pattern case. Each of the learned patternsrepresents a different cluster center. In some embodiments, differentcluster centers are generated to produce a representative sampling fortraining. Although generating different cluster centers is not requiredfor producing a representative sampling for training, it can be usefulin creating a more equal distribution over the feature space. In someembodiments, different cluster centers can be generated using principalcomponent analysis. The weighted average (expectation) of these learnedpatterns can be taken as the final heat map. In some embodiments, thefamily of patterns can include binary superpixels (either 0 or 1);affinity propagation, mean-shift, db-scan, patterns generated fromk-means clustering learned from a training set; patterns generated fromPCA over a training set; and low frequency DCT patterns.

FIG. 20 illustrates examples involving the use of images representingthe expectation taken over the predicted distribution of local binarysuper pixels in 2000. These examples represent non-limiting examples ofusing pseudo multi-label classification. RGB images 2002, 2006, and 2010can be inputs to a classifier using pseudo multi-label classification.The classifier can generate the corresponding output heat map images2004, 2008, and 2012, respectively. In some embodiments, by using pseudomulti-label classification, the output can be reduced to a relativelysmall number of coefficients (e.g., several hundreds) that can representimage segmentations. This can increase processing speed and save storagespace.

FIG. 21 illustrates a method 2100 of generating a label image based on aparameter set according to some embodiments of the present disclosure.In some embodiments, method 2100 can be modified by, for example, havingsteps combined, divided, rearranged, changed, added, and/or removed. Insome embodiments, method 2100 can be performed at an object detector. Insome embodiments, the object detector can be located in the imageryanalysis server 2604 or any other suitable location of the system 2600.

At step 2102, training images can be received. The training images caninclude one or more pixels. In some embodiments, these training imagescan be the same image type. For example, these training images are allof one of the following image types: RGB, IR, and UV. In someembodiments, each of the training images is one of RGB, panchromatic,IR, UV, multi-spectral, hyperspectral, and/or any other suitable image.In some embodiments, an image can include two or more co-registeredchannels or bands of electromagnetic spectrum. For example, an image caninclude RGB and IR.

At step 2104, training parameter sets can be received. In someembodiments, each training parameter set can correspond to one or morelabels that have been transformed using a transformation technique, suchas DCT, wavelets, discrete Fourier transform, PCA, NMF, Hadamardtransform, and/or any other suitable transformation. In someembodiments, the one or more labels can correspond to a differenttraining image. In some embodiments, every training image corresponds toa training parameter set that represents labels for the training image.

At step 2106, a classifier can be created based on the training imagesand the parameter sets. The classifier can be configured to determine aparameter set for an image. In some embodiments, the classifier can becreated using a machine learning system, such as an ANN or a CNN aswould be appreciated by one of ordinary skill in the art.

At step 2108, a target image is received. At step 2110, a targetparameter set that corresponds to one or more labels for the targetimage can be determined using the trained classifier. In someembodiments, this classifier is the classifier created at step 2106. Insome embodiments, the target parameter set can correspond to one or morelabels that have been transformed using a transformation technique, suchas DCT, wavelets, discrete Fourier transform, PCA, NMF, and Hadamardtransform. In some embodiments, the target image is one of RGB,panchromatic, IR, UV, multi-spectral, hyperspectral, and/or any othersuitable image.

At step 2112, a label image can be generated by applying an inversetransformation to the target parameter set. For example, if the targetparameter set generated at step 2110 corresponds to DCT, then an inversetransformation of DCT can be applied to this target parameter set toproduce a label image or label map. In some embodiments, one or morepixels of the segmented image can be associated with a class. Forexample, a particular pixel of the label image can be associated with aroof. In some embodiments, the class can be two-class. In otherembodiments, the class can be multi-class. An example of step 2112 isdescribed in connection with FIG. 24 below.

In some embodiments, method 2100 can also include receiving othertraining parameter sets for the training images. For example, a trainingparameter set can include at least one of time, date, sun direction, sunposition, latitude, longitude, and/or any other suitable parameter orcombination of parameters. In some embodiments, this additionalinformation from the training parameter sets can be related tocorresponding training images. For example, the time value can berelated to the time when the training image was captured. As anotherexample, the latitude value can be related to the latitude of thelocation where the training image was captured. In some embodiments, theadditional information from the training parameter sets can increase theaccuracy of the classifier.

FIG. 22 illustrates an example input and output of the classifier asdescribed in connection with FIG. 21 . Multi-label classifier 2204 is anexample of a classifier created from step 2106 in FIG. 21 . Multi-labelclassifier 2204 can receive an input, such as RGB image 2202 (e.g., fromstep 2108 in FIG. 21 ), and produce a segmented image 2206 (e.g., a heatmap generated from step 2112 in FIG. 21 ). In some embodiments,segmented image 2206 can be represented as a heat map.

FIG. 23 illustrates an example input to a pseudo multi-label classifier2304 that can take an image 2302 (e.g., RGB image) as input and generatea parameter set 2306 as output. The parameter set 2306 can characterizean associated implicit label map under an orthogonal transformation(e.g., DCT, PCA, etc.). Non-limiting examples include the use of a CNNas the pseudo multi-label classifier 2304.

FIG. 24 illustrates an example parameter set 2402 and a label map 2406that is formed from the parameter set 2402. The parameter set 2402 isbased on an orthogonal transformation using DCT. An image 2404illustrates the 2D DCT frequencies that form the basis functions of theDCT transformation. A symbol 2408 represents applying the inverse DCT.The inverse DCT can be applied with correct normalization and summingover all the basis functions from the image 2404, where the product ofeach basis function and its corresponding coefficient in the parameterset 2402 is calculated. The resulting image can be a label map 2406,which can be a heat map that can show a class associated with each pixelof the segmented image. In some embodiments, a non-DCT transformationcan be used instead of the DCT transformation.

FIG. 35 illustrates an example of using an object detector according tosome embodiments of the present disclosure. Object detector 3504 canimplement a method of generating a label image using a parameter set.For example, object detector 3504 can implement one or more steps ofmethod 2100 (FIG. 21 ). Objector detector 3504 can take and process aninput image, such as RGB image 3502. The output can be a label image.For example, the resulting label image can be a heat map 3506, where thelight regions (e.g., light region 3508) show the roofs in the image andthe dark regions (e.g., dark region 3510) show other structures.

Experiment Data

The accuracy and precision of the output from an object detector usingmachine learning can vary depending on many factors. These factorsinclude, for example, the object detection method used, the type ofinput, the complexity of the input, the amount of data used in trainingthe object detector, the quality of the data used in training the objectdetector, and the similarity between the training data and the input.For example, the more similar the input is to the training data, themore accurate the output is. As another example, using a large amount oftraining data can generally result in a more accurate output compared tousing a small amount of training data.

FIG. 36 illustrates ground truth data 3604 generated from an RGB image3602 as input. Ground truth data 3604 can be considered accurate, andthus, it can represent the reference data, to which experimental datacan be compared. In some embodiments, the ground truth data 3604 can begenerated manually using, for example, an interactive polygon editingtool. This ground truth data 3604 can be used to compare with theoutputs from an object detector. FIGS. 37-39 illustrate using the sameinput as FIG. 36 (e.g., RGB image 3602). The outputs shown in thesefigures are, however, different because they use different objectdetection methods. The experimental data described in FIGS. 37-39 is forillustrative purposes.

FIG. 37 illustrates a binary output 3702 generated from using a hybridsegmentation method, such as method 300 (FIG. 3 ). The binary output3702 can be evaluated for accuracy using ground truth data 3604. Anotherform of heat map 3704 can be used to show the level of accuracy for thebinary output 3702. For example, an area where the color is the same orsimilar to segment 3706 (e.g., light gray) indicates that the area hasbeen accurately segmented. A pixel in this area can be called a “truepixel.” On the other hand, an area where the color is the same orsimilar to segment 3708 (e.g., dark gray) indicates that the area hasnot been accurately segmented. A pixel in this area can be called a“false pixel.” In some embodiments, segmentation of an area can beconsidered accurate if the level of accuracy exceeds a threshold value.For example, given an area, if the percentage of an object in the areais correctly identified by the binary output 3702 as compared to groundtruth data 3604, and the percentage exceeds a threshold value,segmentation of that area can be considered accurate. Moreover, a truepositive occurs at a pixel when the observation (e.g., results of adisclosed system such as the binary output 3702) and the ground truthdata both indicate the foreground at the pixel. A false positive occursat a pixel when the observation indicates the foreground and the groundtruth data indicates the background at the pixel. A false negativeoccurs at a pixel when the observation indicates the background and theground truth data indicates the foreground at the pixel.

FIG. 38 illustrates a binary output 3802 generated from using a pseudomulti-label classification method, such as method 2100 (FIG. 21 ).Similar to heat map 3704 (FIG. 37 ), heat map 3804 can be used to showthe level of accuracy for the binary output 3802. Heat map 3804 showsthe resulting evaluation of this output, which is compared againstground truth data 3604.

FIG. 39 illustrates binary output 3902 generated from using a fullyconvolutional network(s) (FCN) with a pseudo multi-label classificationmethod. The FCN(s) can be used to convert all fully-connected layers ofa CNN into equivalent convolutional layers. This can allow input imagesof arbitrary size to be processed in one forward pass through thenetwork instead of using separate image chips in their own forwardpasses. Consequently, the convolutional kernels in FCN(s) are requiredto be evaluated only once, independent of the actual number of chipsthat take them into account for classification. Similar to heat map 3704(FIG. 37 ), heat map 3904 can be used to show the level of accuracy forthe binary output 3902.

Machine Learning for Geometry Extraction Digital Elevation and HeightMaps from Multiple Images

Elevation is taken to be relative to a global reference (e.g., mean sealevel). Height is taken to be relative to local environment (e.g., theheight of buildings above the surface of neighbors). With one or moreimages of the same area, an above ground height model (AGHM) image canbe generated using a classifier, where every pixel of the AGHM image canbe assigned to a height above ground. The classifier can estimateelevations or heights of geographic regions and/or objects in images bydirect or relative prediction without performing feature search orextraction. The classifier can generate an AGHM based on the estimation.In some embodiments, the elevations and heights can be represented as aheat map. In some embodiments, the specified geographic regions orobjects can be determined relative to a baseline elevation. For example,the baseline elevation can be the ground elevation. Using the groundelevation, each object height, such as a building height, can berelative to the ground on which it stands. In other embodiments, thebaseline elevation can be sea level.

FIG. 25 illustrates an example RGB image 2502 and an example AGHM image2504. In some embodiments, a classifier can be created so that it takesin an RGB image (e.g., as shown in 2502) as an input and generates anAGHM image (e.g., as shown in 2504) as output.

In some embodiments, two types of images—a digital surface model (DSM)and a digital elevation model (DEM)—can be used to generate AGHM images.A DSM can represent the elevation of the tops of all reflected surfaces,including both natural and built environments. A DEM image can show thebaseline ground elevation without any structure (e.g., buildings) orvegetation (e.g., trees). In some embodiments, the DEM is a 3D surfacemodel. In some embodiments, a model (e.g., DSM, DEM) can be a 2D surfacethat resides in 3D. In some embodiments, a model can be a 2D surfacethat projects into a 2D map. In some embodiments, a model can refer toboth the 3D and 2D variants. The height above ground can be derived bytaking the difference between the DSM and the DEM. Using thisdifference, the object height that is relative to the ground on which itstands can be determined. Both DSM and DEM can be derived, for example,from LIDAR or stereo reconstruction. Stereo reconstruction can involvetaking two or more images of the same object from different locations.

A machine learning network can be trained to learn methods—such asphotogrammetric techniques (e.g., stereo rectification) and variants ofblock-matching techniques—to determine the disparity or shift betweenmatching points across multiple images. These methods can further relyon explicit regularization and smoothing frameworks (e.g., Markov RandomFields) to ensure that nearby or neighboring pixels have similar depthvalues and that depth values for each pixel are not far from theiroriginal estimates. In some embodiments, a machine learning network canbe trained to learn these methods within the context of a deep neuralnetwork (DNN).

In some embodiments, common key points in different images can beidentified. The relative distance between these common key points oneach respective image can be used to estimate the location of thecamera/aperture and/or the location of each key point.

In some embodiments, a machine learning network can use one or more ofthe following data items for training to create a classifier: two ormore raw 2D images; ground sampling distance (GSD); relative estimatedcamera/aperture locations for each image; camera location; and an AGHMas ground-truth. In some embodiments, machine learning uses an ANN or aCNN. In some embodiments, a trained classifier can receive 2D images andoptionally the camera location(s), and output an AGHM.

Machine learning has many advantages. For example, a machine-learneddevice does not require handcrafted feature design and extraction,classical stereo-rectification, epipolar geometry, and block-matching.The device can also accommodate regions of homogeneous intensity orcolor. The device does not need explicit regularization. Moreover, it isedge-preserving, which is desired for subsequent processing, such assegmentation.

During the training stage, the label space for the classifier can be aheat map, whose ground truth can be derived from LIDAR measurements orclassical stereo vision. For example, LIDAR measurements can be in theform of point clouds or derived data such AGHMs. In some embodiments,the training can be performed with single pixels, such as sparse 3DLIDAR points. During the test or execution stage of the classifier, theoutput can be a heat map.

Different feature spaces can be used to train a network. Below is adescription of four non-limiting examples of feature spaces.

First, a feature space can include a set of images defining the samegeographic area taken from sensors, whose relative pose (translation androtation) is fixed. For example, images can be taken from one nadirsensor and four oblique sensors configured in a circular pattern.“Nadir” and “oblique” refer to the orientation of the sensor relative tothe ground target. A nadir sensor can point directly below at its target(e.g., camera axis is vertical relative to its target). An obliquesensor can point at angle to its target. The network can be trained justfor this particular “stereo” or “n-focal rig.” Both the intrinsic cameraparameters (e.g., pinhole camera matrix and those related to lensdistortion) and the extrinsic camera parameters (e.g., relative positionand orientation of camera to a world coordinate system) can be implicitto the model. In other words, these intrinsic and extrinsic cameraparameters may not need to be directly estimated.

Second, a feature space can include a set of images defining the samegeographic area taken from sensors whose relative pose is not fixed. Thefeature space can further include a set of relative poses and intrinsicparameters of these sensors. For example, the pose can be represented asa 6 real-valued number, and each sensor can have real-valued numbers asits parameters. The network can take in these additional parameters inaddition to the images.

Third, a feature space can include a set of images, all of which areprojected onto the same geographic surface (e.g., WGS84 withweb-mercator), defining the same geographic area. An example includesimage tiles which lie in the same coordinate space. The set of relativeposes and camera parameters—both intrinsic and extrinsic—is implicit tothe model and can be learned by the network. The network can be trainedjust for a specific “stereo-rig” or “n-focal-rig.”

Fourth, a feature space can include a set of images, all of which areprojected onto the same geographic surface (e.g., WGS84 withweb-mercator), defining the same geographic area. In contrast to thethird example, the set of relative poses and camera parameters—bothintrinsic and extrinsic—are part of the feature space. In other words,this set is explicitly given as input to the network. Consequently, thenetwork is not only trained for a specific “stereo-rig” or“n-focal-rig,” but also can be used for multiple configurations.

For all types of features spaces, including the example feature spacesdescribed above, dense reconstruction can be achieved, for example, byapplying the training method to scaled images followed by, inpost-processing, interpolation/regularization techniques, such astriangulation and Markov Random Fields.

FIGS. 33A-D illustrate example parameter values related to a sensor inaccordance with certain embodiments of the present disclosure. FIG. 33Aillustrates extrinsic camera parameters. The R_(x), R_(y), and R_(z)refer to rotation about three cardinal axes in a reference frame. TheT_(x), T_(y), and T_(z) refer to translation in a reference frame. FIG.33B illustrates intrinsic camera parameters. The focal_(x) and focal_(y)refer to focal length in cardinal dimension in an image. The skew refersto shear distortion. The ppt_(x) and ppt_(y) refer to the principalpoint in an image. FIG. 33C illustrates date, time, latitude, andlongitude. FIG. 33D illustrates lens distortion parameters. The kappaand tau parameters refer to radial and tangential distortioncoefficients often associated with lens.

FIGS. 10A-C illustrate an example set of a DSM image, a DEM image, andan AGH image, respectively, in accordance with certain embodiments ofthe present disclosure. In FIG. 10A, DSM image 1002A is a grayscaleimage, where various heights of the objects in DSM image 1002A areindicated by varying shades of grayscale. For example, the brighter thecolor (e.g., closer to white), the higher up the indicated object isfrom a reference level (e.g., higher elevation), compared to the darkercolor (e.g., closer to black). In some embodiments, the brighter thecolor indicates, the closer the object is to the sensor or camera thatcaptured the image from above the object. Legend 1004A provides mappingbetween a spectrum of brightness to an elevation of a given point(measured on top surface). The elevation can, for example, be measuredin reference to above the sea level. Legend 1004A provides a range ofelevations of about 1310 meters to 1380 meters.

In FIG. 10B, DEM image 1002B is a grayscale image, where the height ofeach pixel that represents the area in the image is indicated by varyingshades of grayscale. For example, the brighter the color (e.g., closerto white), the higher up the indicated area is from a reference level(e.g., higher elevation), compared to the darker color (e.g., closer toblack). In some embodiments, the brighter the color, the closer the areais to the sensor or camera that captured the image from above the area.Legend 1004B provides mapping between a spectrum of brightness to anelevation of a given point (measured from a top surface). The elevationcan, for example, be measured in reference to above the sea level.Legend 1004B provides a range of elevations of about 1310 meters to justover 1360 meters. In some embodiments, these elevations are the baselineground elevations without any built structure or vegetation.

In FIG. 10C, AGH image 1002C is a grayscale image that is generatedbased on DSM image 1002A and DEM image 1002B. Legend 1004C provides amapping between a spectrum of brightness to an AGH of a given point. Insome embodiments, AGH image 1002C can be generated by subtracting theelevation given in DEM image 1002B from the elevation given in DSM image1002A for every pixel.

FIGS. 11A-C illustrate another example set of a DSM image, a DEM image,and an AGH image, respectively, in accordance with certain embodimentsof the present disclosure. In FIG. 11A, DSM image 1102A is a grayscaleimage, where various heights of the objects in DSM image 1102A areindicated by varying shades of grayscale. For example, the brighter thecolor (e.g., closer to white), the higher up the indicated object isfrom a reference level (e.g., higher elevation), compared to the darkercolor (e.g., closer to black). In some embodiments, the brighter thecolor indicates, the closer the object is to the sensor or camera thatcaptured the image from above the object. Legend 1104A provides mappingbetween a spectrum of brightness to an elevation of a given point(measured on top surface). The elevation can, for example, be measuredin reference to above the sea level. Legend 1104A provides a range ofelevations of about 1342 meters to 1350 meters.

In FIG. 11B, DEM image 1102B is a grayscale image, where the height ofeach pixel that represents the area in the image is indicated by varyingshades of grayscale. For example, the brighter the color (e.g., closerto white), the higher up the indicated area is from a reference level(e.g., higher elevation), compared to the darker color (e.g., closer toblack). In some embodiments, the brighter the color, the closer the areais to the sensor or camera that captured the image from above the area.Legend 1104B provides mapping between a spectrum of brightness to anelevation of a given point (measured from a top surface). The elevationcan, for example, be measured in reference to above the sea level.Legend 1104B provides a range of elevations of about 1342 meters toabout 1350 meters. In some embodiments, these elevations are thebaseline ground elevations without any built structure or vegetation.

In FIG. 11C, AGH image 1102C is a grayscale image that is generatedbased on DSM image 1102A and DEM image 1102B. Legend 1104C provides amapping between a spectrum of brightness to an AGH of a given point. Insome embodiments, AGH image 1102C can be generated by subtracting theelevation given in DEM image 1102B from the elevation given in DSM image1102A for every pixel.

Elevations and elevation ranges are not limited to those described inFIGS. 10A-C and 11A-C. Elevations can be any numbers, and elevationranges can be any range of numbers.

FIG. 12 illustrates a method 1200 of determining heights of one or moreregions in an image according to some embodiments of the presentdisclosure. In some embodiments, method 1200 can be modified by, forexample, having steps combined, divided, rearranged, changed, added,and/or removed. In some embodiments, method 1200 can be performed at anextractor. In some embodiments, method 1200 can use one of the fourfeature spaces described above.

At step 1202, training images can be received. In some embodiments, eachof the training images is one of RGB, panchromatic, IR, UV,multi-spectral, hyperspectral, and/or any other suitable image. In someembodiments, each training image can include one or more regions, whereeach region includes one or more pixels. The training images can includeone or more pixels. In some embodiments, these training images can bethe same image type. For example, these training images are all of oneof the following image types: RGB, IR, and UV. In some embodiments, thetraining images can be from one or more sensors. In some embodiments,the one or more sensors can be at fixed positions. In some embodiments,in addition to the training images, parameters related to theposition(s) of the sensor(s), orientations of the sensors relative toone another, and/or orientation of illumination source that associatesformation of the training images can be received. Examples of theseparameters can include, for example, time, date, sun direction, sunposition, latitude, longitude, and/or any other suitable parameter orcombination of parameters. In some embodiments, a latitude and/or alongitude are coordinate(s) for the position of a sensor. In otherembodiments, a latitude and/or a longitude are coordinate(s) for theposition of an object or an image. In some embodiments, parametersrelated to positions of the sensor(s) that are configured to capture thetraining images can be received. In some embodiments, the trainingimages can be projected onto a same geographic surface that defines theregion(s).

At step 1204, labels can be received. In some embodiments, each of theselabels can indicate a height for one or more pixels of a region. In someembodiments, a label can indicate a height for more than one pixel thatrepresents one or more regions.

At step 1206, a regression model can be created based on the receivedtraining images and the received training labels. The regression modelcan be configured to determine a height of one or more regions of animage. In some embodiments, the regression model can be created using amachine learning system, such as an ANN or a CNN as would be appreciatedby one of ordinary skill in the art.

At step 1208, a target image can be received as an input to theregression model. In some embodiments, the target image is one of RGB,panchromatic, IR, UV, multi-spectral, hyperspectral, and/or any othersuitable image. The target image can have one or more target regions. Insome embodiments, the target image is the same type as the trainingimages. For example, if the training images are RGB, the target imagecan also be RGB. In other embodiments, the target image is a differenttype from the training images. In some embodiments, when the targetimage is a different type from the training images, the target image canbe transformed to the same type as the training images.

At step 1210, one or more heights of the one or more target regions canbe determined using the regression model. In some embodiments, thisregression model is the regression model created at step 1206.

In some embodiments, during both the training stage and execution stage,additional parameters can be received. These additional parameters caninclude parameters related to (1) positions of the one or more sensorsand (2) orientation of illumination source that associates formation ofthe training images. Examples of these parameters include time, date,sun direction, sun position, latitude, longitude, and/or any othersuitable parameter or combination of parameters.

FIG. 13 illustrates example images in a feature space 1302 and a labelspace 1304. Feature space 1302 includes two input images—Input₁ andInput₂. Label space 1304 includes one input image, which is an AGHMimage. An extractor 1306 can take these three images as input, inaddition to other images, for training and creating a regression modelthat is configured to determine the heights of different regions in animage.

Surface Roughness (Object Height) from Shadows

Given a nadir image, traditional computer vision methods use shadows,date, time, and geographic position (latitude and longitude) informationto triangulate height. These methods, however, require a significantamount of human interaction, and thus are slow and expensive. Moreover,these methods are not robust in the presence of vegetation because it isdifficult to automatically detect shadow lines on uneven and clutteredsurfaces, although in remote sensing images, there is typically enoughinformation for humans to infer shadow lines, if not the height ofstructures.

Disclosed methods and systems can directly estimate the elevation orheight of a specified region or object from various types of images,such as those from monocular imagery. The elevation or height can berelative to a baseline elevation and can be represented as a heat map.For example, the baseline elevation can be the ground elevation. Usingthe ground elevation, each object height, such as a building height, canbe relative to the ground on which it stands. In other embodiments, thebaseline elevation can be the sea level.

A machine learning network can be trained on what humans can directlysee such that there is no need to segment shadows or extract shadowboundary features which may be noisy. In some embodiments, a machinelearning network can be trained to learn these methods within thecontext of an ANN, a DNN or a CNN as would be appreciated by one ofordinary skill in the art.

The machine learning network can be trained with various types of data,such as data regarding building height and location (e.g., AGHM andtable of values), images of buildings (e.g., nadir or near-nadirimagery), and information regarding the location of the camera and thesun.

During the training stage, the label space for the classifier can be aheat map, whose ground truth can be derived from LIDAR measurements orclassical stereo vision. For example, LIDAR measurements can be in theform of point clouds or derived data such AGHMs. In some embodiments,the training can be performed with single pixels, such as sparse 3DLIDAR points.

The feature space can include an image representing a geographic area; adate and time; and a geographic point (latitude and longitude). In someembodiments, a set of date and time and a set of latitude and longitudeare encoded as real-valued numbers. These two sets can infer thedirection of the sun-light when and where the image is acquired.

For all types of features spaces, including the example feature spacedescribed above, dense reconstruction can be achieved, for example, byapplying the training method to scaled images followed by, inpost-processing, interpolation/regularization techniques, such astriangulation and Markov Random Fields.

After the machine learning network has been trained, a classifier can becreated such that it can receive a single image (e.g., nadir image) andparameters such as sun and camera locations. Using these input values,the classifier can output height estimates, a DEM, or a “roughness map.”In some embodiments, the roughness map is analogous to an AGHM but onlyoffers relative height changes or roughness. The output can be in theform of a heat map or a set of values. In some embodiments, ageometry-based model can be built, where shadows from a 3D model aregenerated by the known light position and compared to the input data.

Roof Pitch from Shading Using Deep Learning

Traditional computer vision methods cannot automatically distinguish thepitch of a rooftop from a monocular nadir image. Manual methods requirehumans to make certain assumptions and include additional data.

Disclosed methods and systems can automatically distinguish roof pitchfrom images. For a given roof, disclosed methods and systems can alsoestimate the roof's dominant pitch. For example, given an image thatincludes a roof, a disclosed method or system can take the image as aninput and determine the dominant pitch of the roof (e.g., as 30degrees).

A machine learning network, such as a CNN, can be trained with imagessuch as monocular images; location and heat map of structures ofinterest; and/or ground truth regarding roof pitch for each building.The images may contain visible and/or non-visible bands (e.g., IR). Anadvantage lies in having many bands that provide complimentaryinformation. Explicit modeling of reflectance can involve materialconstants with respect to Lambertian Law and other techniques.

In some embodiments, the machine learning network can be trained furtherwith information regarding camera and sun location, hyperspectralimagery, multispectral imagery, and/or differential intensity gradientsin various spectrums.

Given multiple faces of the same roof of the same material, the machinelearning network can estimate the pitch by using computer graphicsmodels, such as lighting and shading models.

During the training stage, the label space for the classifier can be asingle real-valued number that represents the dominant pitch. Forexample, the dominant pitch can be expressed in degrees or percentages.

Different feature spaces can be used to train a network. Here, twonon-limiting example feature spaces are provided. First, a feature spacecan include an image or set of images representing a roof. A network canbe trained for a given combination of date, time, and geographicposition (latitude and longitude). Second, a feature space can includean image or a set of images representing a roof along with a date, atime, and a geographic position (latitude and longitude) as real-valuednumbers. The non-imagery portion of this feature space can be used toinfer the direction of the sun-light at the location and/or time ofimage acquisition. The non-imagery portion can also be given through anormalization pre-processing of the input image. For example, the inputimage can be rotated so that the sun direction is from the South and theshadows are cast Northward. The input image can further be scaled sothat the shadow cast by a roof of fixed height is always the same sizein pixels.

After the machine learning network has been trained, the classifier cantake the appearances of each face in multiple spectra (e.g., RGB, IR)and a model that describes the reflectance of the sun light from asurface with given material properties. Additionally, the materialconstants can be estimated whenever a sufficient number of facets arevisible. The output of the production classifier can include a map ofthe buildings and roof pitch.

FIG. 14 illustrates method 1400 for determining a geometric objectproperty according to some embodiments of the present disclosure. Insome embodiments, method 1400 can be modified by, for example, havingsteps combined, divided, rearranged, changed, added, and/or removed. Insome embodiments, method 1400 can be performed at an extractor.

At step 1402, training images can be received. In some embodiments, eachof the training images is one of RGB, panchromatic, IR, UV,multi-spectral, hyperspectral, and/or any other suitable image. In someembodiments, these training images can be the same image type. Forexample, these training images are all of one of the following imagetypes: RGB, IR, and UV.

At step 1404, a geometric object that corresponds to a portion of thetraining image(s) can be received. In some embodiments, a geometricobject can be at least one of a point, a contour, an area, or a binarymask on a training image. In some embodiments, a geometric object can beother suitable portions of the training image. The geometric objects canbe used to point to objects or regions of interest in the trainingimages. For example, if a geometric object is an area on a trainingimage, the geometric object can be used to point to the area that coversthe boundary of a building of interest in the training image.

At step 1406, training geometric object properties can be received. Eachgeometric object property can identify a corresponding geometric objectby, for example, identifying a property or attribute of thecorresponding geometric object. In some embodiments, a geometric objectproperty can be one of slope, pitch, dominant pitch, material, area,height, or volume. For example, if a corresponding geometric object is aroof, the geometric object property can identify the pitch of the roof.

At step 1408, parameters related to the orientation of an illuminationsource for the training images can be received. These parameters caninclude at least one of time, date, sun direction, sun position,latitude, longitude, object material, and/or any other suitableparameter or combination of parameters. In some embodiments, one or moreof these parameters can provide information from the formation of thetraining images. For example, if a training image of a location is takenat 3:05 pm on Jul. 1, 2000, where the location's latitude is 64.2008degrees North and the longitude is 149.4937 degrees West, one or more ofthe following can be used for training: 3:05 pm, Jul. 1, 2000, 64.2008degrees North, and 149.4937 degrees West.

At step 1410, a classifier and/or a regression model can be createdbased on the training images, the geometric object, the traininggeometric object properties, and the parameters for the training images.The classifier and/or the regression model can be configured todetermine a geometric object property for an image. In some embodiments,the classifier and/or the regression model can be created using amachine learning system, such as an ANN or a CNN as would be appreciatedby one of ordinary skill in the art.

At step 1412, a target image and a target geometric object thatcorresponds to a portion of the target image can be received. In someembodiments, the target image is one of RGB, panchromatic, IR, UV,multi-spectral, hyperspectral, and/or any other suitable image. In someembodiments, the target image can be the same image type as the imagetype of the training images. For example, the image type of the targetimage and the training images are all RGB. In some embodiments, a targetgeometric object can be at least one of a point, a contour, an area, ora binary mask on a training image. In some embodiments, a targetgeometric object can be other suitable portions of the target image. Thetarget geometric objects can be used to point to objects or regions ofinterest in the target image. For example, if a target geometric objectis an area on the target image, the target geometric object can be usedto point to the area that covers the boundary of a building of interestin the target image.

At step 1414, parameters related to the orientation of an illuminationsource for the target image can be received. These parameters caninclude at least one of time, date, sun direction, sun position,latitude, longitude, object material, and/or any other suitableparameter or combination of parameters. In some embodiments, theseparameters for the target image can be the same type of parameters asfor the training images. In some embodiments, one or more of theseparameters can provide information from the formation of the targetimage.

At step 1416, a target geometric object property can be determined. Thetarget geometric object property can identify a corresponding geometricobject by, for example, identifying a property or attribute of thecorresponding geometric object. In some embodiments, the targetgeometric object property can be one of slope, pitch, dominant pitch,material, area, height, or volume. For example, if the correspondinggeometric object is a roof, the target geometric object property canidentify the dominant pitch of the roof.

FIG. 34 illustrates an example of determining a geometric objectproperty according to some embodiments of the present disclosure. RGBimage 3402 can be an input that is provided to an extractor. In someembodiments, the extractor can implement one or more steps of method1400 (FIG. 14 ). The extractor can detect that there is an object ofinterest 3406. In this example, object of interest 3406 is a pool. Insome embodiments, object of interest 3406 can be outlined on a differentbackground as shown in image 3404 than the original image (RGB image3402). In some embodiments, the object of interest 3406 can beidentified automatically by using a method, such as method 300 (FIG. 3). In other embodiments, the object of interest can be identifiedmanually. The extractor can identify a target geometric object propertyfor the object of interest 3406. For example, the extractor candetermine that the area of the pool is 40 m² as shown in 3410. In someembodiments, the target geometric object property can be displayed ontop of RGB image 3402 as shown in image 3408.

Deep Learning for Alignment Machine Learning Multi-Modal Image StackRegistration

In the domain of recovering structure from remote or aerial imaging, itmay be useful to align images of the same scene that are acquired underdisparate illumination conditions, viewing geometries, and sensor typesand configurations. Traditional computer vision methods use discretefeature matching, feature distance functions, and regularizationcomponents in an optimization that are explicitly and separatelydefined. Traditional computer vision methods also use informationtheoretic distances or rely on jointly estimating the transformation andan underlying structural model.

These traditional methods, however, are not scalable, can beinefficient, and can be inaccurate. For example, the traditional methodsface difficulty in matching features across disparate bands as thefeature appearance can be radically different (e.g., IR band UV band).As another example, the information theoretic distances described abovedo not scale well with a number of bands.

To solve these problems, systems and methods according to someembodiments of the present disclosure can apply machine learning, suchas DNNs, to multi-modality image registration by learning the parametersof a geometric transformation that maps the space of one image into thatof another. These systems and methods can extend to mapping one imageset (of co-registered images) to another image set (of co-registeredimages). In some embodiments, the terms “channels,” “bands,” and“electronic magnetic spectrums” can be used interchangeably in thecontext of multi-modality.

Parcel alignment is one instance of multi-modal image stackregistration. Parcel alignment techniques, for example, can align an RGBimage with a binary parcel mask.

In some embodiments, the machine learning based parcel alignment methodcan be generalized to the problem of multi-modal image registration,where the binary parcel mask can be replaced with a set of co-registeredgeo-spatial images. In other embodiments, three or more multimodal imagestacks can be simultaneously aligned to a common space (e.g., as inbundle adjustment or unbiased atlas formation). Co-registeredcomplementary images can provide more information to support robustregistration than single channel (mono-modal) images alone.

Vision Based Parcel Alignment

There are various databases of (1) geospatial imagery and sensoryinformation, and (2) parcel boundary information, which can providepolygons describing property lines. It is generally useful to have goodalignment when overlaying parcel boundary information over the top ofimagery or other data layers. This is a known industry challenge formultiple reasons. For example, parcel data can come from disparatedatabases. As another example, boundaries can be defined and encoded indifferent ways or projected on different surfaces.

Imagery, computer vision, and machine learning can be used to derivehints of where parcel boundaries should line up, and then use thesehints for alignment to find a best fit. For example, a method or systemcan identify probable roadways and seek a uniform setback. As anotherexample, a method or system can identify fences, sidewalks or othertypical real property boundaries, and use these for best fit alignment.

The final parcel boundaries can be estimated by using a robust estimatorthat minimizes joint distances from all hints, using a distortion model.Example techniques for transformation include similarity, perspective,thin-plate-splines, piece-wise affine, B-Splines, and higher orderbivariate polynomials.

Machine Learning Based Parcel Alignment

Another approach to parcel based alignment involves learning theparameters of a transformation that maps the space of geospatial imagery(and optionally, co-registered sensory information such as IR) to thespace of parcel boundaries (encoded as binary mask images) using machinelearning methods including, but not limited to, CNNs. Once thistransformation, which is represented by a set of parameters, is learned,the parcel boundaries can be mapped to the space of geospatial imagery.The learned transformation can be global or local, and can be recoveredin a multi-scale fashion. A transformation can be global if thetransformation is applied uniformly to every pixel within an image. Atransformation can be local if different parameters of thetransformation are used to define the transformation in differentregions of the image. Multi-scale in this setting can refer to: (1) (inresolution) the use of a learned transformation at a course level ofspatial resolution to initialize the estimation of a transformation at afiner level of spatial resolution; and/or (2) (in transformationparameter complexity) the use of learned transformation of a low order(e.g., translation) to initialize the estimation of a transformation ofhigher order (e.g., thin-plate-splines). Example techniques fortransformation include similarity, perspective, thin-plate-splines,piece-wise affine, B-Splines, and higher order bivariate polynomials.These transformations can be characterized as sets of real-valuednumbers.

FIG. 15 illustrates a method of training a classifier model (e.g., aCNN) for learning the parameters of a transformation that maps the spaceof geospatial imagery to the space of parcel boundaries in accordancewith certain embodiments of the present disclosure. Steps 1502, 1504,and 1506 can be executed during the training stage; steps 1508 and 1510can be executed during the test stage. At step 1502, a pseudo-random setof transformation can be generated from a selected transformation group.At step 1504, for a given geospatial image and associated parcel datapair, each pseudo-random transformation can be applied to the givenparcel data, thereby producing a family of deformed parcels all basedoff the original images. In some embodiments, this process can berepeated for many geospatial images and associated parcel data pairs.

In some embodiments, the input feature space to the classifier can bedefined to be the set of geospatial images (and optionally,co-registered sensory information such as infrared) and deformed parceldata. The output label space can be defined to be the associatedpseudo-random transformations. At step 1506, the classifier model can betrained using these input-output pairs from step 1504.

At the test stage, the trained CNN model can be first applied togeospatial imagery (and, optionally, co-registered sensory information)and an associated novel instance of parcel mask to produce thetransformation (step 1508). At step 1510, using this transformation, theinput parcel mask can be deformed or resampled to the space of thegeospatial imagery. In some embodiments, the parcel mask alignment canbe refined iteratively by deforming the parcel mask with the outputparameters from the trained classifier and repeating process untilconvergence is achieved. Example tests of convergence can includeclassifier model cost function minimization, preset maximum number ofiterations, and normed change in transformation parameters falls below aset threshold.

Machine Learning for Alignment Via Direct Estimation of TransformationParameters

In some embodiments, techniques described above related to parcelalignment can be generalized to alignment via direct estimation.Transformation parameters can be used for this purpose.

FIG. 16 illustrates a method 1600 of identifying parameters of atransformation that maps a first type of image set to a second type ofimage set in accordance with some embodiments of the present disclosure.In some embodiments, method 1600 can be modified by, for example, havingsteps combined, divided, rearranged, changed, added, and/or removed. Insome embodiments, method 1600 can be performed at an aligning device.

At step 1602, a first type of image sets can be received. In someembodiments, each first type of image set can include one or more firsttype of images. In some embodiments, one or more of the first type ofimage sets can include two or more co-registered images. Co-registeredimages can refer to aligned images, where specific pixel coordinates ofthose images represent the identical physical location (e.g., a locationon the surface of the Earth, often expressed as a latitude andlongitude). Consequently, these co-registered images can share, at leastin part, the same scene. In some embodiments, one or more of the firsttype of image sets can include a fixed image stack of co-registeredimages of disparate bands in the electromagnetic spectrum. In someembodiments, the first type of image sets is one of RGB, panchromatic,IR, UV, multi-spectral, hyperspectral, and/or any other suitable image.

At step 1604, a second type of image sets can be received. In someembodiments, the number of the received first type of image sets can bethe same as the number of the received second type of image sets. Insome embodiments, each of the second type of image sets can be alignedwith a different one of the first type of image sets. In someembodiments, one or more of the second type of image sets can includemoving image stack of co-registered images of disparate bands in theelectromagnetic spectrum. In some embodiments, the moving image stackcan be co-registered with the fixed image stack from step 1602. In someembodiments, the second type can be a parcel map. In some embodiments,the second type of image sets is one of RGB, panchromatic, IR, UV,multi-spectral, hyperspectral, and/or any other suitable image.

At step 1606, transform parameters can be generated. In someembodiments, one or more of these transform parameters are generatedusing a computer randomizer that can produce pseudo random data. In someembodiments, the number and/or type of generated transform parameterscan be customized. In some embodiments, the number and/or type ofgenerated transform parameters can be either statically or dynamicallyset.

At step 1608, the transformed second type of image sets can begenerated. In some embodiments, these transformed second type of imagesets can be generated for each of the first type of image sets, whereeach of the transformed second type of image sets for each of the firsttype of image sets can be generated by transforming a respective one ofthe second type of image sets using a different one of the transformparameters. For example, the moving image stack from step 1604 can bedeformed based on the generated transform parameters from step 1606. Insome embodiments, this transformation results in the total number oftransformed second type of image sets that equals the number of thesecond type of image sets multiplied by the number of transformparameters. In some embodiments, the operations in step 1608 can producethe ground truth.

At step 1610, a regressor can be created based on the first type ofimage sets, the transform parameters, and the transformed second type ofimage sets. In some embodiments, the regressor can be trained to learn atransformation as would be appreciated by one of ordinary skill in theart. The regressor can be configured, given a first type of image setand a second type of image set, to identify parameters of atransformation that maps the second type of image set to the first typeof image set.

At step 1612, a target first type of image set can be received. In someembodiments, the target first type of image set is one of RGB,panchromatic, IR, UV, multi-spectral, hyperspectral, and/or any othersuitable image.

At step 1614, a target second type of image set can be received. In someembodiments, the target second type of image set is one of RGB,panchromatic, IR, UV, multi-spectral, hyperspectral, and/or any othersuitable image.

At step 1616, a target transform parameter can be generated using theregressor based on the received target first type of image set and thereceived target second type of image set.

At step 1618, a transformed target second type of images can begenerated by transforming the target second type of image set using thetarget transform parameters so that the transformed target second typeof image set can be aligned with the target first type of image set.

Convergence in transformation between multiple images or image sets candepend on the amount of alignment between them. A condition for meetingconvergence in transformation can be set statically or dynamically. Forexample, a condition can be set such that convergence in transformationis met if two images align for more than 80% (or any other suitablepercentage) of their pixels. In some embodiments, a method or system candetermine whether convergence in transformation is met. If convergenceis not met, steps 1614, 1616, and/or 1618 can be repeated. In someembodiments, these steps can be repeated until convergence intransformation is met.

The transform parameters and the target transform parameter can begenerated and/or used for various transformation techniques, such astranslation, similarity, perspective, thin-plate-splines, piece-wiseaffine, B-spline, and high-order bivariate polynomials. In someembodiments, all the transform parameters and the target transformparameter can use the same technique (e.g., one of the above listedtechnique).

FIG. 17 illustrates a training example that uses a sample input 1702,transform parameters 1704, and pairs of feature space and transformparameters 1706. Sample input 1702 can include an RGB image (a firsttype of image set) and a parcel ground truth image (a second type ofimage set). Sample input 1702 can represent example types of data thatcan be used at steps 1602 and 1604 (FIG. 16 ). In some embodiments, analigning device can generate transform parameters 1704. In someembodiments, the aligning device can generate one or more of thesetransform parameters by using a computer randomizer that can producepseudo random data. In some embodiments, the number and/or type ofgenerated transform parameters can be customized. In some embodiments,the number and/or type of generated transform parameters can be eitherstatically or dynamically set. This set of parameters can represent anexample type of transform parameters generated at step 1606 (FIG. 16 ).In 1706, a feature space can have a number of sample pairs of images.The first image in a pair (e.g., image 1708) can represent an RGB image,while the second image (e.g., image 1710) in the pair can represent aparcel ground truth image that has been transformed using one of thetransform parameters (e.g., transform parameters 1712). These samplepairs can be examples of transformed second type of image sets fromsteps 1608 (FIG. 16 ).

Weighting of Low Resolution Channels with High Resolution AsynchronousOverlay

There are certain use cases for which one may have multiple sets ofgeospatial data, none of which are sufficient to answer a givenquestion. But once overlaid, aligned, and used to inform one another,accurate inferences can be drawn.

For example, one may want to determine roof material, and in particular,distinguish wood shingles from brown asphalt shingles or othermaterials. One may have access to accurate, high resolution (e.g., 30 cmGSD), low cost imagery in RGB. This imagery can be used to locate and/oridentify clean unobscured patches of roof. However, at this resolutionbrown asphalt shingles may be indistinguishable from brown wood shakeshingles in RGB. Further, one may have access to low resolution (e.g.,1.5 m GSD) hyperspectral imagery. This imagery can differentiate betweenasphalt and wood based on hyperspectral reflectance, but this lowresolution may be unable to determine whether a patch of roof isobscured (e.g., with a solar panel, skylight, shadow, etc.) and likelyto give an inaccurate reading.

By overlaying the RGB (for accurate masking in the x-y dimensions) andhyperspectral (to obtain signal in the relevant wavelength), one canmake an accurate estimate in cases such as the example above. These twoimage sets may be obtained from different platforms at different times.For example, hyperspectral data from a satellite can be received on agiven day and RGB data can be received from an airplane at a later date.The imagery can be aligned based on coordinates, where the images can beassumed to be of the same object.

Another example can be overlaying a DEM, which is accurate inz-dimension (height), but must be accurately aligned in x-y using higherresolution RGB imagery.

FIG. 19A illustrates an example RGB image, which is within visiblebands. FIG. 19B illustrates eight example images of differentmulti-spectral bands that are associated with the RGB image in FIG. 19A.Each of these example images corresponds to light response in discretebands in the electromagnetic spectrum. Analogously, the red, green, bluebands are sensitive to light centered near 645 nm, 555n, and 470 nmrespectively. Two or more images of different multi-spectral bands canbe combined to classify ground material (e.g., vegetation and rooftypes).

Mixed Image Resolution/Modality Alignment

Systems and methods in accordance with the present disclosure can aligntwo or more raster images with disparate modalities, such asresolutions, bands, and/or electronic magnetic spectrums. In someembodiments, machine learning is used for estimating corresponding keypoints across images of disparate modalities and identify transformparameters using these key points. Using these transform parameters, twoor more images with disparate modalities can be aligned. Once they arealigned, they can be combined to draw inferences about the scene theydescribe. These systems and methods solve problems in traditionalmethods, where hand crafting matching key-point feature extractionacross multiple modalities (e.g., IR band vs. UV band) is a difficulttask. These traditional methods often rely on sparsely populated jointdistribution of image intensities or estimation of underlying structure,which can be inaccurate and are not scalable.

FIG. 18 illustrates a method 1800 of aligning images based onidentifying a second type of image set given a first type of image setin accordance with some embodiments of the present disclosure. In someembodiments, method 1800 can be modified by, for example, having stepscombined, divided, rearranged, changed, added, and/or removed. In someembodiments, method 1800 can be performed at an aligning device.

At step 1802, a first type of image sets can be received. In someembodiments, each first type of image set can include one or more firsttype of images. In some embodiments, one or more of the first type ofimage sets can include two or more co-registered images. In someembodiments, one or more of the first type of image sets can include afixed image stack of co-registered images of disparate bands in theelectromagnetic spectrum. In some embodiments, the first type of imagesets is one of RGB, panchromatic, IR, UV, multi-spectral, hyperspectral,and/or any other suitable image.

At step 1804, a second type of image sets can be received. In someembodiments, the number of the received second type of image sets can bethe same as the number of the received first type of image sets. In someembodiments, each of the second type of image sets can be aligned with adifferent one of the first type of image sets. In some embodiments, oneor more of the second type of image sets can include moving image stackof co-registered images of disparate bands in the electromagneticspectrum. In some embodiments, the moving image stack can beco-registered with the fixed image stack from step 1802. In someembodiments, the second type of image sets is one of RGB, panchromatic,IR, UV, multi-spectral, hyperspectral, and/or any other suitable image.

At step 1806, a regressor can be created based on the first type ofimage sets and the second type of image sets. In some embodiments, theregressor can be created based on learning an association between imagestacks of the first type and the image stacks of the second type. Theregressor can be configured, given a first type of image set, toidentify a second type of image set.

At step 1808, a target first type of image set and first key points ofthe first type of image set can be received. In some embodiments, one ormore of the first key points can be objects that have been identifiedmanually, semi-manually, or automatically. In some embodiments, anobject detector, such as the one described in FIG. 3 , can be used todetect one or more of the first key points. In some embodiments, thetarget first type of image set is one of RGB, panchromatic, IR, UV,multi-spectral, hyperspectral, and/or any other suitable image.

At step 1810, a target second type of image set can be received. In someembodiments, the target second type of image set is one of RGB,panchromatic, IR, UV, multi-spectral, hyperspectral, and/or any othersuitable image.

At step 1812, the target first type of image set can be divided intofirst divisions. In some embodiments, each of the first divisions can becentered around a different one of the first key points.

At step 1814, second divisions of the target second type of image setcan be generated based on the first divisions. At step 1816, second keypoints can be identified, where each second key point is from adifferent division of the second divisions. In some embodiments, anobject detector, such as the one described in FIG. 3 , can be used todetect one or more of the second key points.

At step 1818, transform parameters can be identified. These transformparameters can map the second key points to the first key points. Atstep 1820, a transformed target second type of image set can begenerated by transforming the target second type of image set using thetransform parameter so that the transformed target second type of imageset is aligned with the target first type of image set. For example, thefirst key points may be associated with roofs in the target first typeof images, and the second key points may be associated with roofs in thetarget second type of images. To map and align each roof from the targetfirst type of image set to the corresponding roof from the target secondtype of image set, the target second type of images can be transformedusing the transform parameters. In some embodiments, these transformparameters are similar in the format as example target parameters 1704shown in FIG. 17 .

Convergence in transformation between multiple images or image sets candepend on the amount of alignment between them. A condition for meetingconvergence in transformation can be set statically or dynamically. Forexample, a condition can be set such that convergence in transformationis met if two images align for more than 80% (or any other suitablepercentage) of their pixels. In some embodiments, a method or system candetermine whether convergence in transformation is met. If convergenceis not met, a different transform parameter can be selected and used fortransforming the target second type of image set. In some embodiments,the process of using a different transform parameters to transform thetarget second type of image set can be repeated until convergence ismet.

The transform parameters can be generated and/or used for varioustransformation techniques, such as translation, similarity, perspective,thin-plate-splines, piece-wise affine, B-spline, and high-orderbivariate polynomials. In some embodiments, all the transform parameterscan use the same technique (e.g., one of the above-listed techniques).

Geospatial Change Detection

It can be useful and valuable to flag some geospatial changes as ofinterest or not of interest. This can be a laborious process whenexecuted manually. Examples of geospatial changes that may be ofinterest include moss on roof, shingle loss, hurricane ripping off roof,additions to existing structures, and introduction of new structures.Examples of geospatial changes that may not be of interest include snowon roof and seasonal foliage present on roof.

In some embodiments, a classifier can be trained to take an image anddetermine whether there has been a change. If there has been a change,the classifier can further determine whether the change is significantor not significant. In some embodiments, object-oriented deep learningcan be used for change detection. For example, the presence of a poolcan be determined. As another example, areas of material change can beidentified. In some embodiments, parameter changes can be reported.

In some embodiments, a list of changes that are of interest can becreated. For example, such a list can include information on whethersomeone can build an addition, can cut a tree, the presence of a pool,and the presence of a patio.

Humans can look at images to determine whether a change has occurred. Aneural network in accordance with some embodiments is a structural formused in deep learning that can know, for example, whether the leaves ona tree is a change of consequence. For example, if information relatedto whether the leaves have fallen off the tree is of interest, theleaves on the tree can be a change of consequence. In some embodiments,crowd source can be utilized to generate ground-truth labeling ofobjects.

Tree Size Analyzer/Estimator

In some embodiments, a tree size analyzer or estimator can usegeospatial imagery combined with other data sets to create informationof interest. For example, given satellite imagery (e.g., 12″ GSD RGB, aswell as hyperspectral), a tree's diameter and the tree type can beestimated by using the geometry and texture to guess the tree type. Oncean estimate of diameter and type are known, a full tree model can bedeveloped based on a separate database of tree growth models. Forexample, an evergreen tree has a certain shape, meaning that a givendiameter can be predictive of a certain height, trunk diameter, boughdiameter, and/or mass.

Information from the tree analyzer can be useful, for example, inestimating the potential damage related to a tree falling on a nearbystructure.

Best Guess of Occluded Polygons

It can be useful and valuable to estimate the underlying shape of anoccluded polygon. For example, in a nadir image, the shape of the cornerof a house can be estimated even if occluded by an overhanging tree. Inthis context, a dictionary or library of template shapes to be matchedto partially-defined polygons can be maintained. FIG. 31 illustrates anexample of a library of template shapes. The different shapes within thedictionary or library can capture the expected modes of variation in theoccluded polygons to be estimated. This can be solved with severalapproaches. One approach can involve the following five steps: (1)segment regions (e.g., houses, trees); (2) fit polygons to segmentedregions; (3) where house regions are adjacent to tree regions, assumeoccluded house regions may underlay the tree regions; (4) useintersection of rectilinear borders of house regions to predict hiddenvertices; and (5) construct new house polygon using rectilinear edgesand vertices including hidden vertices. Another approach can involve thefollowing three steps: (1) learn or define a set of likely polygons orpolygon rules (e.g., rectilinear, 90 degree vertices, etc.); (2) segmenthouse and tree regions; and (3) fit polygon from defined library basedon segmentation, and regarding tree segments as uncertain.

Autoencoders for Satellite and Aerial Imagery

An autoencoder in an artificial neural network can be used to learn arepresentation (or an encoding) for a set of data (often digitalimages). It can be viewed as a generative model in that images can bereconstructed from this representation. FIGS. 32A-B illustrate anapplication of autoencoders to multiple machine learning tasks inaccordance with some embodiments of the present disclosure. Block 3200Aillustrates that the structure of an autoencoder is like an hourglasswith input images (e.g., image 3202A) on one end fed through the firsthalf of the network (e.g., the encoder stage 3204A) to the neck (e.g.,code 3206A) and then through the second half of the network (e.g., thedecoder stage 3208A) producing the same image (e.g., image 3210A). Insome embodiments, autoencoders can be trained to extract the essence ofaerial and satellite images that serves to remove redundant informationand noise (compression) as well as capture low-level features thatcharacterize this type imagery.

In some embodiments, an autoencoder (e.g., the encoder 3202B) can befirst trained. Subsequently, the resulting encoder half can be used totrain a family of networks each for a different purpose (e.g., roofpixel classification) as illustrated in block 3200B. Decoder 3204B canbe used to decode any code encoded by encoder 3202B to generate labels.This approach has additional advantages including (1) training theautoencoder can be fast since ground truth is, by construction, readilyavailable (e.g., any geospatial imagery will) and (2) training newlydesigned networks are easier since the encoder stage is performed onlyonce.

Geospatial Image Label Transfer

When trying to automatically identify objects from images using learningalgorithms, it can be advantageous to have labeled images and/or labeledattributes. Separately, acquired images require tradeoffs betweenresolution, coverage, cost and frequency.

In the case of geospatial images, multiple sets of images can sharecommon, known locations. The images of a common location can beidentified via their GIS metadata, and the labels can be shared ortransferred. This can be valuable in the following example case: (1)costly high resolution images are gathered and labeled by hand; and (2)these labels are transferred to satellite imagery which is of poorerpixel resolution and could not be labeled by hand for certain features(e.g., roof material). But where there remains a sufficient signal inthe data, a useful classifier can still be trained to recognize theattribute in satellite data

Alternatively, this can also be called geospatial image registration andmasking. This can be relevant when there are multiple geospatial datasets that cover the same physical area (e.g., 2 sets of images, both ofwhich can be geo-registered and overlap the same area on the surface ofthe earth). The core concept is to use one of the data sets to defineareas of intersect (e.g., using high resolution RGB imagery to find aclean spot on a rooftop), and a second dataset to extract additionalinformation about the region of interest (e.g., information from ahyperspectral image in the region of interest in order to determine roofmaterial type, which could not be known from the RGB data alone). Thiscan also be used, for example, by getting a digital elevation map fromone image source, and a shadow map from a second source, then using thedigital elevation map to extract height information from the shadowsmapped onto the digital elevation map surface.

Distinguishing Roof Types

It can be useful and valuable to distinguish roof material attributes(e.g., wood vs tile shingles), as well as roof age at scale. Non-optimaldata, such as low resolution satellite images, can be used. A givenmaterial can behave in a certain way with respect to reflectance, givenknown parameters (e.g., sun spectrum/angle/intensity, camera angles),and desired parameters (e.g., age, material). The desired parameters canbe extracted from the image based on the hyperspectral data (outsidevisible range). Calibration can be performed based on (1) ground truth,and (2) an image classifier.

Additionally, the image data can be made more accurate by properlyselecting and sampling uniform aspects of the roof (e.g., on a commonplane; avoiding edges; devoid of shadows, roof debris, and structuressuch as A/C units or skylights).

From nadir imagery, relative geometry of roof joints (where facets ofthe roof meet along a ridge) can provide cues for roof geometry. Using atexture-based edge detector, a skeleton of the roof projection can beconstructed (e.g., rejecting solar panel roof boundaries). Moreinformation can be gathered from a medial axis representation estimatedfrom the roof boundary using traditional techniques (or vice versa). Therelative geometry of roof joints (e.g., encoded using histograms ofnumber of angles at an intersection of ridges, and perhaps lengths ofincident edges) can characterize roof type and complexity.

Roof Pitch from Drone Aerial Imagery

Classical computer vision methods can be applied to recovering roofpitch from aerial images (e.g., from airplanes and drones), globalpositioning systems (GPS), inertial measurement units (IMUs), andgyroscopes. These methods include a range of techniques from recoveringdepth from stereo to the more sophisticated structure from motion (SFM)where bundle adjustment and graph optimization methods are used withimages acquired around and above roofs to reconstruct shape. In allmethods, the optimization process is constrained to planar surfaces,suitable for structures of the built environment.

Roof footprints localized on the acquired imagery, or mapped to the samefrom another geospatial imagery source, can be used to identify facet(planar surfaces) to roof associations. Estimating the dihedral anglesmade by these facets and a horizontal ground plane produce the roofpitch.

Roof Pitch from Shading

From a 3D roof model, the calculation of pitch/slope of a roof facetimmediately follows from geometry. In this method, a 3D roof model isfitted using both spatial and appearance information. Shadinginformation can be used as a cue for form, position, and depth (inparticular, roof facet orientation) and depends on material properties.Non-limiting examples of shading model components include: ambientreflection, diffuse (Lambertian) reflection, specular reflection, etc.Given a sufficient number of input image channels (e.g., RGB,panchromatic, IR, UV, multi-spectral, hyperspectral, etc.), roof facetorientation and intrinsic color/texture (proxy for material) can beestimated using a shading model.

In another embodiment, the parameter space of this model (e.g.,intrinsic color, facet orientation, etc.) can be reduced using anycombination of (but not limited to) the following simplifyingassumptions: (1) roof ridge lines are parallel to horizontal groundplane; (2) neighboring roof facets incident to the same ridge line aresymmetric in the sense that they have the same pitch/slope; and/or (3)the space of allowable roof pitch/slope is limited to a discrete set ofcommon values. Non-limiting examples of parameters include values ofrun/rise that are 12/1, 12/2, 12/3, etc., where the run value can bedefined to be the horizontal length, and the rise value can be definedto be the vertical length of a general right triangle, whose hypotenuseis the roof surface. The roof surface can be used to calculate the roofpitch or slope.

Condition Estimation

In some embodiments, systems and methods can be utilized to estimateconditions of a road, parcel, and/or roof (e.g., effective age).

It is to be understood that the disclosed subject matter is not limitedin its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The disclosed subject matter is capable ofother embodiments and of being practiced and carried out in variousways. Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting. Unless otherwise noted, examples provided in thisdisclosure are not limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, systems and methods for carryingout the several purposes of the disclosed subject matter. It isimportant, therefore, that the claims be regarded as including suchequivalent constructions insofar as they do not depart from the spiritand scope of the disclosed subject matter.

Although the disclosed subject matter has been described and illustratedin the foregoing exemplary embodiments, it is understood that thepresent disclosure has been made only by way of example, and thatnumerous changes in the details of implementation of the disclosedsubject matter may be made without departing from the spirit and scopeof the disclosed subject matter, which is limited only by the claimswhich follow.

For example, a device, such as an object detector or an aligning device,can cover implementations in a single hardware/software device or inmultiple hardware/software devices. In some embodiments, each of themultiple hardware/software devices can process different parts of thedevice functionality.

As another example, machine learning can cover various deep learningarchitectures, including a deep neural network (DNN), a convolutionalneural network (CNN), a deep belief network (DBN), and a recurrentneural network (RNN). Moreover, a reference to a particular architecturedoes not limit the given application to that particular architecture.Systems and methods in accordance with embodiments of this disclosurecan be applied to any type of machine learning or deep learningarchitecture.

Yet in another example, unless otherwise noted, the term image can coverany kind of image from any detectable band of the electromagneticspectrum, including IR, UV, panchromatic, multi-spectral, orhyperspectral images. An image can be RGB, grayscale, or black andwhite. An image can be any resolution, including high resolution and lowresolution. An image may be taken by various methods and/or devices,including satellites, drones, robots, stationary or moving camera orsensor devices, and humans using a camera or sensor device. An image maybe taken as a digital image or as an analog image. An image may havebeen originated as an analog image but later converted to a digitalformat. An image can indicate a 2D array of pixels with one or moremutually co-registered channels or bands per pixel, summarizing the samearea. Non-limiting examples include (1) a 1-channel image that can be apanchromatic image, a grayscale image, a label map, a binary mask, orany other suitable image with one channel; (2) a 3-channel image thatcan be an RGB image, a blue-green-red (BGR) image, or any other suitableimage with three channels; (3) a 4-channel image that can be an RGB andIR image or any other suitable image with four channels; and (4) a8-channel image that can be an 8-band multi-spectral image. Generally,the channels can represent different bands of the electromagneticspectrum, to which a detector is sensitive.

What is claimed is:
 1. A method of generating a label image based on aparameter set, comprising: receiving, at an object detector, trainingimages; receiving, at the object detector, training parameter sets,wherein each of the training parameter sets corresponds to a transformedrepresentation of one or more labels, and wherein the one or more labelscorrespond to a different training image; creating, at the objectdetector, a classifier configured to determine a parameter set for animage based on the training images and the training parameter sets;receiving, at the object detector, a target image; determining, at theobject detector using the classifier, a target parameter set thatcorresponds to one or more target labels for the target image, whereinthe target parameter set corresponds to a target transformedrepresentation of the one or more target labels; and generating, at theobject detector, a label image by applying an inverse target parameterset to the target image, wherein the inverse target parameter setcorresponds to an inverse transformation of a transformation representedby the target parameter set, wherein one or more pixels of the labelimage are associated with a class.
 2. The method of claim 1, whereineach of the one or more classes is either two-class or multi-class. 3.The method of claim 1 further comprising receiving second trainingparameter sets for the training images, wherein the second trainingparameter sets comprise at least one of time, date, sun direction, sunposition, latitude, or longitude.
 4. The method of claim 1, wherein eachof the training parameters sets and the target parameter set representsa transformation created using one of discrete cosine transform,wavelets, discrete Fourier transform, principal component analysis,non-negative Matrix Factorization, or Hadamard transform.
 5. The methodof claim 1, wherein each of the training images and the target image isone of a red-green-blue, panchromatic, infrared, ultraviolet,multi-spectral, or hyperspectral image.